Frontlines: a Python Tower Defence Game

A 2D tower defence game written in Python with Pygame. Enemies march along a winding path in waves that get bigger and tougher each round. You spend money to place towers that track and shoot them before they reach the other side of the map.

I built it to practise object-oriented programming and real-time game logic: a 60 FPS game loop, moving entities, collision detection and an in-game economy. It was developed over three prototypes.

🎥 Demo: Prototype 1 validation video

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How to play

1. Launch the game. On the main menu, click Start. Use Settings to set the music volume.
2. Click a tower in the shop at the bottom of the screen, then click on the map to place it. Press Esc to cancel.
3. Towers fire at enemies in range on their own. Each kill earns money and score, so you can build more.
4. If an enemy gets off the right-hand edge of the map, it's Game Over. Click Play Again to retry.

Tower	Cost	Damage per shot
Tower 1	100	40
Tower 2	200	65

You start with 200 money. Each kill gives +20 money and +100 score.

Features

• Wave system. A new wave spawns when the last one is cleared. Waves start at 4 enemies, gain one more every 4 rounds (up to 15), and enemy health grows each round.
• Path following. Enemies follow a set route across the map, with turns at fixed waypoints.
• Targeting and projectiles. Each tower finds an enemy within its 150 px range. Towers spread their fire so two towers don't waste shots on the same enemy. Projectiles home in on their target using atan2, and the sprite rotates to face the direction it's flying.
• Fire-rate cooldowns. Each tower can fire once every 450 ms, tracked per tower with a dictionary of timestamps.
• Placement rules. A tower can't be placed off-screen, on top of another tower, or on an enemy. A preview follows the mouse until you click.
• Economy and HUD. Money, score and the current round are shown on screen and update live.
• Menus and audio. A main menu with background music, a settings screen with a custom-built volume slider wired to Pygame's audio mixer, and a Game Over screen with Play Again.

How the code is organised

Class	File	Responsibility
Tower	Prototype 1/tower.py	Tower stats, range checks, choosing targets, firing and cooldowns, money and score
TowerSelection(Tower)	Prototype 1/tower.py	Inherits from Tower; handles shop selection, the placement preview and validating where a tower can go
Projectile	Prototype 1/tower.py	Homing movement, sprite rotation and hit detection
EnemyGroup	Prototype 1/tower.py	Spawning waves, scaling health and moving enemies along the path
MainLoop	Prototype 1/tower.py	The 60 FPS game loop: input, update, draw, HUD and game-over checks
MenuLoop, SettingsScreen(MenuLoop)	Prototype 2/main menu.py	Main menu and settings screen
VolumeSlider	Prototype 2/main menu.py	A draggable slider that maps its position to a 0–100 volume
Main	Prototype 3/game over.py	Game Over screen and Play Again

OOP ideas used:

• Encapsulation: private (__) and protected (_) attributes.
• Inheritance: TowerSelection from Tower, and SettingsScreen from MenuLoop.
• Composition: MainLoop owns the tower system and the enemy group.

Development: three prototypes

1. Prototype 1, the core game: map, enemy waves, path following, towers, projectiles, economy and HUD.
2. Prototype 2, the main menu: Start and Settings buttons, menu music and the volume slider.
3. Prototype 3, Game Over: an end screen that relaunches the game.

The menu, game and Game Over screen are separate scripts that launch each other with subprocess.

Running it

Requirements: Python 3.8+ and Pygame, on Windows. The asset paths use Windows-style separators.

git clone https://github.com/Mathias-D06/Tower-Defence-Game.git
cd Tower-Defence-Game
pip install pygame
python "Prototype 2/main menu.py"

Run the command from the repository's root folder, because the game loads its images and sounds using paths relative to it. Make sure python on your PATH is the interpreter that has Pygame installed, because the menu launches the other screens with that command.

What I'd improve next

• Move to a single game loop with a state machine (menu → playing → game over) instead of launching separate scripts.
• Build asset paths with os.path / pathlib so the game runs on macOS and Linux too.
• Upgradeable towers, more enemy types and a pause button.
• Save high scores between sessions.

Credits

Tower, enemy and projectile sprites come from a free tower defence asset pack. Code by Mathias Dawit.

Use of AI

The game's code and all three prototypes are my own work. Claude (Anthropic's AI assistant) was used only to write this README.