Super polished game, the art the music and the controls are really well done :)

I'll be honest, I couldn't finish this game to see the twist, it's so hard, and the slippery controls are really good, games do that, but I just can't get the hang of them

At the start it seemed like the game was straightforward, do the jumps, reach the end and win, but judging by the gameplay video and your description, I suspect there's a different ending to that...

I really think you should post a gameplay video that will show the endings, because I bet this game has something related to the theme but it is hard to get to there, so only the people who are good at Super Meat Boy will be able to see the twist

As for feedback, checkpoints, definitely checkpoints will make the game 10x better, I know it ruins the Stanley Parable vibes but do remember that you're making a hard platformer, while Stanley Parable is a story driven game, which is a lot easier to start over

Great entry though! it seems like you're super experienced because I had no bugs during my playthrough, and it was really fun and engaging, as much as it was frustrating at times