Thank you for the kind words!
Whilst I did try to roughly order them in terms of difficulty, due to lack of playtestering, i was unsure as to how people would find the puzzle's difficulty. Level 5 is definitely an outlier, and should have been placed much earlier on. As for level 2 and 3: 2 was supposed to introduce 3, unless you mean 1 and 2, where level 0 is the tutoral / first level, in which i definitely had mistaken level 1 as being a much easier level. Regardless, I completely understand your feedback & hope it didnt impact your enjoyment of the game too much!
Thank you for playing!