You might have seen my game before, but to follow the scope of this thread, I'll go ahead and post it - the game I'm most proud of:
https://themetalcarrotdev.itch.io/steppingstonejack
To describe the game in additional detail... I'll be straight to the point and say that while the graphics weren't really that inspired by 8-bit games, the gameplay actually was. So this game is very challenging in terms of being a platform game. It doesn't look it from the screenshots, but it just about has that classic Mario or original Sonic level of challenge.
One of the reasons why I'm proud of the game is that the scope of the game was a bit hard to make given my kind of newer level of experience at game development, where making a simpler game could have been more manageable. It wasn't super drastic, but there were a few game development related challenges. So this could have very well been a game that went completely unfinished, I could have made excuses and made something else or something simpler - but I decided to see things through and kind of see what happened.