The first comment on my game after I posted it was "same idea here...", then a link to another game with a similar concept to mine. After checking that one out I went to browse some submissions and was greeted with yet another game with the same concept. Overall, I really enjoyed all three of them, but I noticed that even though we had the same initial concept,  we all took it in a slightly different direction. I definitely tried to focus on actions that require you to combine buttons and making the player juggle those. The second definitely felt like a more traditional platformer shoot'emup that forced you to conserve and plan out your resources, and that third one really played like a puzzle game rather that a platformer.

I definitely had fun with them, and it was interesting to see not just different takes on the same theme, but different takes on the same mechanics.

My game: Full Press

Second Game: Shutting Down by felipedev

Third Game: First Impressions by Mr Rutabaga

Yeah, I stumpled about this PICO-8 game which is build around a very similar mechanic my game is using. In both cases you solve puzzles by holding keys in different colors. The details differ however: the former limits you to one key at a time, that can be used multiple times and destroys it once swapped against a different key. In my game, you can hold multiple keys, but only one per color. Each key will only work one time and is destroyed when used.

I'm still amazed how similar the premise of both games is and how different they turned out still.

I haven't found anything mechanically similar (yet) but I have found one other game that shares a theme.

Single Sighted (mine) and One Pixel both use "only one pixel" specifically referring to the viewport size. Mechanically, however, they couldn't be further apart - mine is a simple exploration game while One Pixel is a precision platformer. I feel like 1x1 viewport as a theme could be diverse enough for a whole game jam itself.

No, but oh my gosh, my runner up idea was to make a 1D game, and SOOOO many people did that. I was amazed, i thought it would be an original concept.

https://newkryptonite.itch.io/the-lonly

Very different execution but I found another one that uses the same idea of having only one second/moment to look at the level. Periodically in my case but for the entire level in the latter!

yup i found two that had the same idea as mine. i thought it was pretty original though );

I found a game that was oddly similar to mine. We both made games about helping Merlin find something -- which seems rather coincidental!

Their game is called "Guide Merlin into the Kingdom" and ours is called "Merlin's Mess"

I actually don't know the names of the similar ones but a streamer played mine and said it wasn't that original and there were other ones with the same idea but implemented better, it kinda got me down but most people are saying positive things about it. If you know any of the games like this please reply with them. https://itch.io/jam/gmtk-2019/rate/461359

Yep I'm another one with the same concept as you! https://itch.io/jam/gmtk-2019/rate/463424