Thanks for your detailed feedback!
I used fixed update but I didn't use Time.deltaTime unfortunately :( I am really sorry for that.
Levels being sometimes impossible was intentional, you ask why?
Spoiler:
Cause I wanted to show that killing your enemies (pulling them down in our world) doesn't always mean that we would reach our goals.
You have seen the ending right? XD
Thanks a lot for playing and commenting ;D