I spent a couple days on a balance type game where you had a character you tried to keep on a see-saw type object but other items would rain down and affect the weight balance. I had a few levels done but just wasn't having a whole lot of fun with it. As soon as I thought of another idea I scrapped it. I think the process of quickly iterating, then using those lessons on a new game helped out.
Also, organization of my files and using external events ended up being key. I finished with 31 levels, plus menu and a final free-play area, so if I had to keep re-setting items on each level when I made a discovery I would have lost my mind.
Ultimately, this was a blast and I look forward to doing it again. I've wanted to get started in game dev as a hobby for decades and I'm finally taking the time. I'm starting small (and admitting that I have so much to learn), but who knows where it goes from here.
Good luck everyone!