I'm sorry to hear about your experience.
Most of these issues did not occur to me during my hours of game-testing. Although, I did nerf the difficulty of the last level two times, but it appears that was still not enough for some. I only intended it to be difficult enough to lead to a failure or two, but some people can't get past it at all.
Will be making a note of this for my next game jam, as this was my very first one.
Cheers!