Thank you so much for the detailed feedback!
I think the hardest part was probably judging difficulty, I got pretty good at controlling the player during development, so I had no idea where the game was difficulty wise. I think that's also what made me underestimate the enemy placement, for me it was a fun challenge, for others probably a bit frustrating.
This could have been solved by getting some people to playtest it, but I guess you other jammers are the playtesters in this case ^^