PY-L1-41 · Game · Text Adventure — Part 3 (Boss Fight)

Game — Text Adventure, Part 3 (Boss Fight)

The cave has a dragon. Today we build a real combat loop: hero and dragon both have HP, the player can attack or heal, and the dragon strikes back with random damage from random.randint(). The fight ends when one of them hits 0 HP. Built from while-loops, list checks, and a single new built-in. The dramatic Level 1 closer.

⏱ 1 hour🎮 Game lesson📚 After PY-L1-40💻 VS Code or online-python.com

Learning Goals

3 min

By the end of this lesson you can:

Use random.randint(low, high) to roll a random whole-number damage value, inclusive of both ends.
Write a fight loop with while hero_hp > 0 and dragon_hp > 0 — and explain why both conditions appear.
Let the inventory shape the fight: equipping a sword from Part 2 should add to the player's attack roll.

Warm-Up

5 min

You already know random.choice(list) from PY-L1-19. Today we need the sibling — random.randint(a, b) — that returns a whole number between a and b inclusive:

import random

print(random.randint(1, 6))     # like rolling a die — 1, 2, 3, 4, 5, or 6
print(random.randint(5, 10))    # 5, 6, 7, 8, 9 or 10
print(random.randint(0, 1))     # 0 or 1

Quick prediction game. What range of values can random.randint(3, 8) produce?

Show the answer

3, 4, 5, 6, 7, or 8 — six possible values

Both ends are inclusive. That's different from range(3, 8), which stops before 8. randint can land on 8.

The two random tools

random.choice(list) picks one item from a list. random.randint(a, b) picks one number from a range. Together they cover almost every "pick something random" need in a game.

New Concept · The Fight Loop

14 min

Two HPs, one loop

A combat round goes: hero acts (attack or heal), if dragon still standing it attacks back. Repeat until one of them is dead.

hero_hp = 30
dragon_hp = 40

while hero_hp > 0 and dragon_hp > 0:
    # 1. ask hero what they want to do
    # 2. apply hero's action
    # 3. if dragon still alive, dragon attacks back

The and in the condition is essential. As soon as either HP hits 0, the loop ends. That covers both endings — "you win" and "you die".

Hero's action — attack or heal

action = input("ATTACK or HEAL? ").strip().lower()

if action == "attack":
    damage = random.randint(4, 9)
    dragon_hp = dragon_hp - damage
    print("You strike for", damage, "damage. Dragon HP:", dragon_hp)
elif action == "heal":
    heal = random.randint(3, 7)
    hero_hp = hero_hp + heal
    print("You patch yourself up for", heal, ". Hero HP:", hero_hp)
else:
    print("You hesitate. The dragon notices.")

Three branches. Attack rolls damage on the dragon. Heal rolls HP back to the hero. Anything else wastes a turn — the dragon still gets to strike.

Dragon's counter-attack

After the hero's turn, check if the dragon is still up. If so, it hits back:

if dragon_hp > 0:
    bite = random.randint(3, 6)
    hero_hp = hero_hp - bite
    print("Dragon bites for", bite, ". Hero HP:", hero_hp)

That single if is what makes the fight feel fair. If your attack killed the dragon, you don't take a final hit on the way out — the dragon's already dead.

Decide who won after the loop

if hero_hp > 0:
    print("🏆 You defeated the dragon!")
else:
    print("💀 The dragon ate you. The end.")

The loop ended because one of them dropped. Whichever one's HP is still above 0 is the winner.

Inventory shapes the fight

This is the cool moment — if the player picked up a sword in an earlier scene, attacks should hurt more. Just check the bag:

damage = random.randint(4, 9)
if "sword" in inventory:
    damage = damage + 5            # bonus from the sword
    print("(Your sword bites deep!)")

Part 2's inventory finally pays off. Players who explored more of the world before this scene get a meaningful combat advantage.

Rule of thumb

A turn-based fight is one while loop with a combined-condition. Inside: one branch per action, then a follow-up that lets the opponent react only if still alive.

Worked Example · The Dragon in the Cave

14 min

Add the boss to the adventure

We'll change the cave scene from Part 2: instead of immediately winning, the cave now leads into a dragon fight. The fight is a separate function. Save as the latest adventure.py:

Code

# adventure.py — Part 3: dragon fight

import random

def fight_dragon(inventory):
    print()
    print("== DRAGON LAIR ==")
    print("A red dragon coils on its hoard. It opens one ember-yellow eye.")

    hero_hp = 30
    dragon_hp = 40

    while hero_hp > 0 and dragon_hp > 0:
        print()
        print("Hero HP:", hero_hp, " | Dragon HP:", dragon_hp)
        action = input("ATTACK or HEAL? ").strip().lower()

        # hero's turn
        if action == "attack":
            damage = random.randint(4, 9)
            if "sword" in inventory:
                damage = damage + 5
                print("(Your sword bites deep!)")
            dragon_hp = dragon_hp - damage
            print("You strike for", damage, "damage.")
        elif action == "heal":
            heal = random.randint(3, 7)
            hero_hp = hero_hp + heal
            print("You patch yourself for", heal, "HP.")
        else:
            print("You hesitate, distracted by the heat.")

        # dragon's turn — only if it's still alive
        if dragon_hp > 0:
            bite = random.randint(3, 6)
            hero_hp = hero_hp - bite
            print("The dragon bites for", bite, "damage.")

    print()
    if hero_hp > 0:
        print("🏆 The dragon collapses. You loot the hoard!")
        inventory.append("dragon_hoard")
        return "end"
    else:
        print("💀 The dragon's flames consume you. THE END.")
        return "end"


# (the other scenes from Part 2 stay the same; the cave now leads to the fight)
def scene_cave(inventory):
    print()
    print("== CAVE INTERIOR ==")
    if "torch" not in inventory:
        print("Too dark. You stumble back.")
        return "forest"
    print("You walk deeper, torch held high. A great red shape stirs ahead...")
    return "fight"


# main program (snippet — full dispatcher includes village/forest from Part 2)
inventory = []
location = "village"

while True:
    if location == "village":
        location = scene_village(inventory)
    elif location == "forest":
        location = scene_forest(inventory)
    elif location == "cave":
        location = scene_cave(inventory)
    elif location == "fight":
        location = fight_dragon(inventory)
    elif location == "end":
        print()
        print("Final bag:", inventory)
        break
    elif location == "quit":
        print("Goodbye.")
        break

(Re-use your scene_village and scene_forest from Part 2. The cave function changed, and a new fight function plus dispatcher branch are added.)

Sample run · a swordless victory (lucky)

== DRAGON LAIR ==
A red dragon coils on its hoard. It opens one ember-yellow eye.

Hero HP: 30  | Dragon HP: 40
ATTACK or HEAL? attack
You strike for 7 damage.
The dragon bites for 4 damage.

Hero HP: 26  | Dragon HP: 33
ATTACK or HEAL? attack
You strike for 9 damage.
The dragon bites for 6 damage.

... a few more turns ...

Hero HP: 8  | Dragon HP: 4
ATTACK or HEAL? attack
You strike for 6 damage.

🏆 The dragon collapses. You loot the hoard!

Sample run · sword bonus

Hero HP: 30  | Dragon HP: 40
ATTACK or HEAL? attack
(Your sword bites deep!)
You strike for 13 damage.

Things to notice

The hero acts first, then the dragon — only if alive. That order makes the fight winnable. If you let the dragon act before the "is hero dead?" check, you can get a phantom hit after you should've already died.
HP can go above the starting max. The lesson code doesn't cap healing. If you want a cap ("max 30 HP"), use hero_hp = min(hero_hp + heal, 30). Try it as a stretch.
The fight function returns "end" either way. The dispatcher doesn't need to know whether you won or lost — that decision was made and announced inside fight_dragon.

What you just built

A real turn-based RPG fight, with stats, a combat verb system, randomness, and equipment that matters. Less than 40 lines of code, and a complete loop you'll see at the heart of every roguelike. You have a Level 1 adventure with combat. Brag.

Try It Yourself

14 min

Three tasks. Build a tiny fight, then connect it back to the world.

01 🟢 Standalone fight

Open fight_test.py. Hard-code hero_hp = 20 and dragon_hp = 25. Loop while both are above 0. On each turn, attack the dragon for random.randint(3, 7) damage; the dragon hits back for random.randint(2, 5). Print HP after every turn. After the loop, announce who won.

Hint

import random

hero_hp = 20
dragon_hp = 25

while hero_hp > 0 and dragon_hp > 0:
    damage = random.randint(3, 7)
    dragon_hp = dragon_hp - damage
    print("You hit for", damage, "→ dragon HP:", dragon_hp)
    if dragon_hp > 0:
        bite = random.randint(2, 5)
        hero_hp = hero_hp - bite
        print("Dragon bites for", bite, "→ hero HP:", hero_hp)

if hero_hp > 0:
    print("Hero wins!")
else:
    print("Dragon wins!")

Auto-attack version — no input, just two stat blocks bashing each other. Run it three times. Different outcomes each run? Good — that's random doing its job.

02 🟡 Add the heal option

Make the hero choose. input for attack or heal. Heal restores random.randint(3, 6) HP. The dragon still bites every turn. Add a print for the hero's chosen action.

Hint

while hero_hp > 0 and dragon_hp > 0:
    action = input("ATTACK or HEAL? ").strip().lower()

    if action == "attack":
        d = random.randint(3, 7)
        dragon_hp = dragon_hp - d
        print("Hit for", d)
    elif action == "heal":
        h = random.randint(3, 6)
        hero_hp = hero_hp + h
        print("Healed for", h)
    else:
        print("Wasted turn.")

    if dragon_hp > 0:
        b = random.randint(2, 5)
        hero_hp = hero_hp - b
        print("Bitten for", b)

Try the "heal every turn" strategy. Notice you can't actually win that way — the dragon never goes down. Combat needs offence eventually.

03 🔴 Bolt the fight into your adventure (stretch)

Open your adventure.py. Add the fight_dragon(inventory) function from the worked example. Change scene_cave so that, with torch in hand, it returns "fight". Add an elif location == "fight": branch in the dispatcher. Play the full game start-to-finish.

Hint

# in scene_cave, after torch check:
print("You step deeper. A dragon stirs ahead!")
return "fight"

# in main loop:
elif location == "fight":
    location = fight_dragon(inventory)

Three changes — new function, return value tweaked in one scene, one new dispatcher branch. That's how an entire combat system gets bolted into a game without rewriting it.

Mini-Challenge · Yuki's Immortal Dragon

8 min

Yuki's dragon never dies, even when its HP goes negative. Find the two bugs.

# yuki_fight.py — buggy

hero_hp = 30
dragon_hp = 40

while hero_hp > 0 or dragon_hp > 0:        # bug
    damage = random.randint(4, 9)
    dragon_hp = dragon_hp - damage
    print("Hit. Dragon:", dragon_hp)

    bite = random.randint(3, 6)            # bug: no "still alive?" check
    hero_hp = hero_hp - bite
    print("Bitten. Hero:", hero_hp)

print("Done.")

Bug 1. The loop condition uses or instead of and. With or, the loop continues as long as either HP is positive — so the hero (or dragon) keeps getting beaten well past death.
Bug 2. The dragon always attacks, even if its HP already dropped to 0 or below. Wrap the bite in if dragon_hp > 0:.

Show the fix

while hero_hp > 0 and dragon_hp > 0:       # AND, not OR
    damage = random.randint(4, 9)
    dragon_hp = dragon_hp - damage
    print("Hit. Dragon:", dragon_hp)

    if dragon_hp > 0:                       # only if still alive
        bite = random.randint(3, 6)
        hero_hp = hero_hp - bite
        print("Bitten. Hero:", hero_hp)

The and/or mix-up is one of the easiest English-to-code mistakes. "keep fighting while both are alive" in English is and in code — both conditions have to be true together. or would mean "keep fighting while at least one is alive", which is a fight that never properly ends.

Recap

3 min

The adventure is complete. A boss fight is one while loop with a combined condition: keep going while both fighters have HP. Each iteration the hero acts (attack or heal), the action's effect is rolled with random.randint, and if the dragon survives it counter-attacks. The combat hooks into the inventory — a sword in the bag adds damage, so all the exploration from Part 2 actually mattered. After the loop one quick if picks the right ending. Tonight you can wire all three parts together into one continuous game. Next lesson kicks off the three-part Code Wars: bug hunts, output prediction, and a speed round.

Vocabulary Card

random.randint(a, b): Random whole number from a to b, both ends inclusive.
combined loop condition: while X and Y — keep going only while both are true. The fight loop ends the moment either side hits 0.
turn order: The fixed sequence of actions in a round: hero acts, then dragon acts (if alive). Reversing it changes the game.
stat block: The small set of numbers describing a character — HP, damage range, etc. Lives in the function or main program.
equipment bonus: Damage or HP changes based on what's in the inventory. The way exploration translates into combat power.

Homework

4 min

Finish the full adventure tonight.

Combine your Part 1 + Part 2 + Part 3 work into one adventure.py that plays from start to finish — village, forest (with torch), market (with key and sword), cave fight, gate.
Add a scene_market that lets the player pick up a sword. Wire the fight to use it (the worked example already does).
Cap the hero's heal at a max of 30 HP — use min(hero_hp + heal, 30).
Add a small visible "health bar" before each round — e.g. Hero: [#####.....] 25/30. Hint: the bar string is "#" * hero_hp + "." * (30 - hero_hp).

Bring the whole game next class. PY-L1-42 starts the Code Wars trilogy.

Sample · fight_dragon with health bar & cap

def health_bar(hp, max_hp):
    full = max(hp, 0)
    empty = max_hp - full
    return "[" + "#" * full + "." * empty + "] " + str(hp) + "/" + str(max_hp)

def fight_dragon(inventory):
    print("\n== DRAGON LAIR ==")
    hero_hp = 30
    dragon_hp = 40

    while hero_hp > 0 and dragon_hp > 0:
        print()
        print("Hero  ", health_bar(hero_hp, 30))
        print("Dragon", health_bar(dragon_hp, 40))
        action = input("ATTACK or HEAL? ").strip().lower()

        if action == "attack":
            d = random.randint(4, 9)
            if "sword" in inventory:
                d = d + 5
                print("(Sword bonus!)")
            dragon_hp = dragon_hp - d
            print("You hit for", d)
        elif action == "heal":
            h = random.randint(3, 7)
            hero_hp = min(hero_hp + h, 30)
            print("Healed for", h)
        else:
            print("You hesitate.")

        if dragon_hp > 0:
            b = random.randint(3, 6)
            hero_hp = hero_hp - b
            print("Dragon bites for", b)

    print()
    if hero_hp > 0:
        print("🏆 Dragon defeated!")
        inventory.append("dragon_hoard")
    else:
        print("💀 The dragon wins.")
    return "end"

Three nice touches in the sample. health_bar is its own helper function — keeps the fight loop readable. max(hp, 0) guards against negative HP in the bar so you never get a bar with negative #s. And min(hero_hp + heal, 30) is the single-line cap — never go above the max, never below 0 with the bar guard.

Game — Text Adventure, Part 3 (Boss Fight)

⏱ 1 hour🎮 Game lesson📚 After PY-L1-40💻 VS Code or online-python.com

action = input("ATTACK or HEAL? ").strip().lower() if action == "attack": damage = random.randint(4, 9) dragon_hp = dragon_hp - damage print("You strike for", damage, "damage. Dragon HP:", dragon_hp) elif action == "heal": heal = random.randint(3, 7) hero_hp = hero_hp + heal print("You patch yourself up for", heal, ". Hero HP:", hero_hp) else: print("You hesitate. The dragon notices.")

# adventure.py — Part 3: dragon fight import random def fight_dragon(inventory): print() print("== DRAGON LAIR ==") print("A red dragon coils on its hoard. It opens one ember-yellow eye.") hero_hp = 30 dragon_hp = 40 while hero_hp > 0 and dragon_hp > 0: print() print("Hero HP:", hero_hp, " | Dragon HP:", dragon_hp) action = input("ATTACK or HEAL? ").strip().lower() # hero's turn if action == "attack": damage = random.randint(4, 9) if "sword" in inventory: damage = damage + 5 print("(Your sword bites deep!)") dragon_hp = dragon_hp - damage print("You strike for", damage, "damage.") elif action == "heal": heal = random.randint(3, 7) hero_hp = hero_hp + heal print("You patch yourself for", heal, "HP.") else: print("You hesitate, distracted by the heat.") # dragon's turn — only if it's still alive if dragon_hp > 0: bite = random.randint(3, 6) hero_hp = hero_hp - bite print("The dragon bites for", bite, "damage.") print() if hero_hp > 0: print("🏆 The dragon collapses. You loot the hoard!") inventory.append("dragon_hoard") return "end" else: print("💀 The dragon's flames consume you. THE END.") return "end" # (the other scenes from Part 2 stay the same; the cave now leads to the fight) def scene_cave(inventory): print() print("== CAVE INTERIOR ==") if "torch" not in inventory: print("Too dark. You stumble back.") return "forest" print("You walk deeper, torch held high. A great red shape stirs ahead...") return "fight" # main program (snippet — full dispatcher includes village/forest from Part 2) inventory = [] location = "village" while True: if location == "village": location = scene_village(inventory) elif location == "forest": location = scene_forest(inventory) elif location == "cave": location = scene_cave(inventory) elif location == "fight": location = fight_dragon(inventory) elif location == "end": print() print("Final bag:", inventory) break elif location == "quit": print("Goodbye.") break

== DRAGON LAIR == A red dragon coils on its hoard. It opens one ember-yellow eye. Hero HP: 30 | Dragon HP: 40 ATTACK or HEAL? attack You strike for 7 damage. The dragon bites for 4 damage. Hero HP: 26 | Dragon HP: 33 ATTACK or HEAL? attack You strike for 9 damage. The dragon bites for 6 damage. ... a few more turns ... Hero HP: 8 | Dragon HP: 4 ATTACK or HEAL? attack You strike for 6 damage. 🏆 The dragon collapses. You loot the hoard!

import random hero_hp = 20 dragon_hp = 25 while hero_hp > 0 and dragon_hp > 0: damage = random.randint(3, 7) dragon_hp = dragon_hp - damage print("You hit for", damage, "→ dragon HP:", dragon_hp) if dragon_hp > 0: bite = random.randint(2, 5) hero_hp = hero_hp - bite print("Dragon bites for", bite, "→ hero HP:", hero_hp) if hero_hp > 0: print("Hero wins!") else: print("Dragon wins!")

while hero_hp > 0 and dragon_hp > 0: action = input("ATTACK or HEAL? ").strip().lower() if action == "attack": d = random.randint(3, 7) dragon_hp = dragon_hp - d print("Hit for", d) elif action == "heal": h = random.randint(3, 6) hero_hp = hero_hp + h print("Healed for", h) else: print("Wasted turn.") if dragon_hp > 0: b = random.randint(2, 5) hero_hp = hero_hp - b print("Bitten for", b)

# yuki_fight.py — buggy hero_hp = 30 dragon_hp = 40 while hero_hp > 0 or dragon_hp > 0: # bug damage = random.randint(4, 9) dragon_hp = dragon_hp - damage print("Hit. Dragon:", dragon_hp) bite = random.randint(3, 6) # bug: no "still alive?" check hero_hp = hero_hp - bite print("Bitten. Hero:", hero_hp) print("Done.")

while hero_hp > 0 and dragon_hp > 0: # AND, not OR damage = random.randint(4, 9) dragon_hp = dragon_hp - damage print("Hit. Dragon:", dragon_hp) if dragon_hp > 0: # only if still alive bite = random.randint(3, 6) hero_hp = hero_hp - bite print("Bitten. Hero:", hero_hp)