Have been playing it quite a bit since the submission as well.
I have to echo the pencil mode being able to win feedback which absolutely ruins it for me - some sequences require penciling quite a bit to find the failing condition which leads to me winning by accident in pencil mode which just feels horrible and sort of cheat-y (I just happend the pencil the winning solution but I didn't solve it as intended)
Overall the game is great and I have been enjoying the daily masters and some of the insane puzzles.
P.S. the submit feedback does not work, something about needing the confirm the form or similar.
Some thoughts:
Insane is not harder than Hard. Often times the opposite seems true.
Scratch mode auto-committing on win is a bit too nice.
Dark mode is whack, terrible contrast.
I would like a player profile with stats and so on.
Random Insane seems to play like one of 50 levels. I recognize them often. Seems not so with hard. Now I just enter the puzzle IDs in turn...
Some puzzles seem to have no prior solutions as my time is often exactly the global average.
I would like to know how many solved a puzzle. Also if I did.
Overall great job and I love this. I would like it to be an app or something that can be bookmarked.