Very simplistic game, I couldn't pass the level with the aliens, not sure why it was not going forward after I got to the platform where the "portal" was.
The movement was wayyy too fast and felt weird, I kept running into lava straightaway when I started. And that's the other thing, I couldn't first tell apart what was killing me, since it was just some color change, didn't pay that much attention (my own fault that one :D)
You made a complete game though, with multiple levels, different death screens ( I enjoyed that) and you explained well in the start how to play so it was relatively good! :) Good job!