Others have pointed out the controls already. What I would specifically change is the max speed. When you think about it, this is a precision-based platformer. Do I really need to be able to get across the room in less than one second? Additionally, the portal hitbox could use some really small adjustments to make it feel more fair. It is easy to clip into the portal on the rising platform, and the tips don't always send me to the other side.
That all being said, I still found myself wanting to finish the game! The visuals are good enough and clear (I like the squish/stretch of the main character!) You clearly focused on quality over quantity of content. Congrats! Hope to see you on the next one.