Thank you all for your comments (and votes)! I really appreciate them.
@Cerno_b, you are right, the puzzles and the route through the game itself could need some work. I especially don't like the map with the same two trees spammed all over it. I had planned for a lot more (more dialogue/text/notes, a less random map, more sounds and so on), but the time was running out, so I had to rush. Being pretty pleased with the outcome, though.
And I was aware of the pixel problem, but didn't think about it much. Don't know if there is some way to solve that, have to reasearch that...
@x1212
YOu are absolutely right, the ending is a bit bad. But I needed to cut that as well due to time problems. That said, the planned ending wouldn't be more satisfying regarding the story, because we just didn't know ourselfs what happened xD (aside from the failed experiment which somehow messed up the world). Just not enough time to think about it ;)