That’s perfectly valid, and I’m glad you made a game that you like to play! I should clarify, improvising solutions isn’t something I dislike in principle. Actually, some amount of that is found in The Incredible Machine. It’s more the perception that I might be handed an impossible puzzle (informed by the text in the instructions) and the fact that as far as I could tell I couldn’t just retry the same puzzle with tweaks made to my setup.
If indeed it’s generally possible to beat a level, I’d highly recommend you just get rid of the note that it might be impossible. If there’s a rare chance of something not working, I’d consider that to be a bug and try to work on solutions to that, rather than warning the player about it.
I’m not sure what you mean when you say that the levels repeat until you beat them. Looking again, I noticed that clicking the “Give Up” button in normal mode over and over again seemed to randomly switch between a couple different basic puzzle templates with randomly distributed objects. I assume the “levels” you’re referring to are those templates? But from my perspective, this is effectively randomly generated puzzles that you can’t repeat. For example, suppose I come up with a solution that’s very close to succeeding, but not quite; I’d like to be able to repeat from where I set it exactly, adjust further, and see if that leads to a solution. Unless there’s some button I didn’t find other than the “Give Up” button, that doesn’t seem to be possible currently.