It is decent, for a beginner it is actually great! I don't think I have to pin-point all the things that could be done better, since this project serves as a learning opportunity for you. However, if you care listen to my advice: the sneaky portal killing players isn't fun. If this was a "rage" game, it would be different, but having players trying seriously and then fooling them in the last level can be frustrating for some. And the doors were a bit confusing. On the other hand, I enjoyed the soundtrack you used and the game didn't really bug out for me, so props on that!