How to Supercharge a Python Alien Invasion Game into a Full‑Featured Shooter

Introduction

The author introduces the second article in the "Python Crawlers and Data Mining" series, referencing the first article and inviting readers to follow the public account for more content.

Original Version Recreation

The original 1.0 version of the alien‑invasion game is presented with screenshots and a list of its basic features:

Player controls a ship (displayed as a cannon) at the bottom of the screen, moving left/right and shooting zombies.

Zombies are arranged in three fixed rows with constant spacing; their number does not change with level.

Player has three lives shown in the top‑left corner; contact with zombies or reaching the bottom reduces a life.

Shooting requires pressing the space key each time; continuous fire is not supported.

The zombie fleet moves horizontally and steps forward when hitting a screen edge; if not cleared quickly, the fleet speeds up.

Only one monster type exists, without health points; higher levels only increase movement speed.

The gameplay is simple, lacking effects, skills, items, or maps.

Score is not persisted between runs; the highest score is lost after the program exits.

Images illustrate the original interface, life icons, score display, level indicator, and the file structure (alien, alien_invasion, bullet, button, game_stats, scoreboard, settings, ship).

The source code for the original version can be downloaded from the provided link.

Modification Plan

1. Eye‑catching UI

The upgraded version, named "Interstellar Frontline," introduces a custom login screen with a start button, a shop toggle (key "s"), and a contact link. The UI uses several images for background, title, play button, shop button, and contact icons.

self.color=(230,230,230)
self.fm = pygame.image.load('images/fm.png').convert_alpha()
self.title = pygame.image.load('images/title.png').convert_alpha()
self.titlerect = pygame.Rect(-190, -60, 1920, 1000)  # rectangle (x,y,width,height)
self.play = pygame.image.load('images/play.png').convert_alpha()
self.playrect = pygame.Rect(645,300, 280, 280)  # rectangle (x,y,width,height)
self.shop = pygame.image.load('images/shop.png').convert_alpha()
self.shoprect = pygame.Rect(0, 700, 330, 158)  # rectangle (x,y,width,height)
self.lianxi1 = pygame.image.load('images/lianxi1.png').convert_alpha()
self.lianxi1rect = pygame.Rect(1330, 780, 187, 80)  # rectangle (x,y,width,height)

self.shop2 = pygame.image.load('images/shop2.png').convert_alpha()
self.shop2rect = pygame.Rect(1395, 735, 140, 126)  # rectangle (x,y,width,height)

2. Diverse maps, monsters, and health

Monster count, health, and speed now scale with the current level. The number of aliens is chosen randomly within a range that grows with the level, and each alien’s health increases at specific thresholds (e.g., level 5, 10, 15, 25, 30, 40, 45, 50). Monsters can also teleport within a short distance to evade bullets. Different enemy types appear at higher levels, including a shielded robot (3 HP) and a boss with a long red health bar. Every ten levels the background map changes.

def _create_fleet(self):
    "创建怪物群1"
    self.alien_bloodmax=1
    self.alien_blood=1
    if self.stats.level>=5:
        self.alien_bloodmax =2
        self.alien_blood = 2
        if self.stats.level >=10:
            self.alien_bloodmax = 3
            self.alien_blood = 3
            if self.stats.level >=15:
                self.settings.guainum = 2
                self.alien_bloodmax =5
                self.alien_blood =5
                if self.stats.level >=25:
                    self.alien_bloodmax =10
                    self.alien_blood =10
                    if self.stats.level >=30:
                        self.alien_bloodmax =20
                        self.alien_blood =20
                        if self.stats.level >=40:
                            self.settings.guainum = 3
                            self.alien_bloodmax =50
                            self.alien_blood =50
                            if self.stats.level >=45:
                                self.alien_bloodmax =100
                                self.alien_blood =100
                                if self.stats.level >=50:
                                    self.alien_bloodmax =150
                                    self.alien_blood =150
    number_alien=random.randint(5+self.stats.level*1,15+self.stats.level*2)
    for row_number in range(number_alien):
        alien = Alien(self)
        self.aliens.add(alien)

3. In‑game shop and economy

The upgraded version adds a shop system. Gold (earned by killing enemies) appears in the top‑left corner, while diamonds (a premium currency) are shown in the top‑right. Hovering over items displays a semi‑transparent tooltip with name, price, category, and description.

self.gaosi1 = pygame.image.load('images/gaosi1.png').convert_alpha()
self.gaosi1rect = pygame.Rect(230, 480, 751, 240)  # rectangle (x,y,width,height)

button3_clicked = self.gaosirect.collidepoint(mouse_pos)
if button3_clicked:
    self.screen.blit(self.gaosi1, self.gaosi1rect)

Conclusion

The author wraps up the first part of the "Super‑Modified Alien Invasion" series, encouraging readers to follow the account for future installments and to share their own modification ideas in the comments or via private message.