Its really hard.

And some music would be nice :)

I like the variety of scenes you're trying out here, but it doesn't feel like much testing went into this.

Colonization: After entering the cave, the first creature you encounter seems impossible to bypass.

Space: When starting, I die almost immediately with no visual signs of anything happening.

Snakes: Interesting but basic platformer which I wasn't able to beat.

Cave Spiders: Interesting to have a maze, but the hallways feel very long for no reason, which makes the whole thing a slow grind, and a few times I got stuck in the terrain and had to force close the game.

I get the feeling you put a lot of time in the art and then had no time for anything else.