The antigravity one was tedious because it took a while to get to the bug, then getting the exact arc needed to get into the file (even after reset). Part of the problem is having to do super tiny steps towards the duck to just keep facing it. Falling ducks was also pretty annoying, but you've removed it already. Other than that level 8 was a little annoying bc of how the camera + arrow keys works when looking from below, and pushing the ducks around can be annoying, but both of these are minor and not that bad when having to do the levels only once (and adds to the "buggy code". 

Side-note, I found the ctrl-shift-enter bug by chance and don't understand what clues were supposed to lead me to it. For level 4 (old 10) I ended up checking the solution, which I'm pretty sure I already tried multiple times, not sure why it didn't register. Couldn't try it after the levels changed since the "bugs found" remained the same.

Folders in the bg was  cool level select.