Space Chase

2D shooter for a Coursera class.

Modifications:

• Collectible items -- power-ups (horizontal diamonds; blue: 20 shots of higher power, green: orbiting shields protecting from projectiles and some types of enemies, red: bonus life) and keys (vertical diamonds, opening a segment of the asteroid wall of the same color of the key).
• Environment modifiable by the collectibles.
• Playable level.
• Inertial movement.
• Big heads-up display with a message describing the collected item.

Created by xofon.

Game walkthrough (spoiler; highlight the text with the mouse to read):

First go to the lower left corner of the starting chamber. Beware of the red planet spawning chaser enemies. Get the blue key. This opens a door to the top chamber, about in the middle of the wall. Go to the top wall of the top chamber (it's easier to evade the projectiles there) and get to the top left corner. Get the red key. This opens a door to the bottom chamber, near where the blue key was earlier. The exit is at the bottom right of the chamber. To pass over a dense row of enemies at the bottom chamber, you can go just above the top row, align the fire direction with the enemy line, and fire, ideally a shotgun. Then you can clear the line left to right. Careful about the spawn location about in the middle. Do the same for a part of the bottom row, starting at the right side. The hole in the bottom wall is the exit.

(Ideally I believe the player should find all of this, including the function of the power-ups, on their own as a part of the game, but a reviewer of my first submission remarked that the purpose of the game is not clear to them, so this may help.)