The base game is already a great start to continue this. I really liked the art style for this and the sound effects. The camera though was probably the biggest detriment. The camera collider and code for keeping the player visible really makes it hard to do some platforming since it would clip into the boxes or go straight into Biboo if you're too close to the boxes or the walls. It made it hard to figure out how to get out or where to go. It might make more sense to do a silhouette shader that shows the player behind the obstacles so the camera doesn't jump around as much. There's also some physics issue if trying to jump against the boxes that makes it so you can't jump at your full height. I got stuck between boxes for a bit due to it. If you fix those two issues, you have a very solid speedrun game.