I do think a randomized world would be pretty fun, especially if you can unlock different abilities to help you get to different places in each run for some meta progression. But I think the procedural generation would've broken me for a 4 day jam ;)
I think one of the reasons the puzzles came out to be simple was having to make sure the player wasn't able to buy anything that would've gotten them stuck, and thus led to making it a get item -> solve -> get item loop. And in turn, I think this made the puzzles rather easy.
Although, I would definitely rather have people complain that the puzzles are too easy, and be able to experience the entire game, over not being able to. I was worried about making anything too difficult due to the non standard game format.
Thank you for the detailed feedback :)