I'm impressed, the core idea of the gameplay is really interesting (it made me think of death squared if you know, not for the timer but for the cooperation) but the puzzle themselves were really well designed! Each one requiring you to resolve something new that you haven't seen before, I loved it!
I didn't manage to beat the last level without looking at the solution, but I managed to beat level 12, 13 and 14 (which I found hard) alone and it was so satisfying to finally reach the end after many many tries.
Congratulation for making that game in such a short time!