So the game has an ending now. It's reached by defeating a flying saucer that can only be damaged by the shockwaves caused by defeating aliens. I'm pretty pleased with the results although I had hoped that I would also had finished a larger part of the map. Right now it's still the starting area and I've just crammed the boss in one of the corners.
Although I did implement level transitioning and a bunch of things that will make it easier to finish the rest of the game.
For tomorrow I will add sound effects and music to the game and also add a way to change the color of the tiles, since the game is, for the most part, supposed to be happening at night.
Controls: Arrow keys for movement, V for confirm, C for cancel.