Had fun to play, there's some serious fun potential here ! Wish there was more levels !
The movement is a bit wonky, the horizontal collisions especially, not much of an issue for a jam game but if you were to make a bigger game it would have to be improved, jumping next to a wall can slow you down and reduce the jump height, stuff like that.
Could be interesting to have triggers that change your value, like a +2, and with zones that prevent you from manually changing your value, so you'd have to pick a value to go through multiple gates so that the operations work correctly.
Maybe an idea could be to have levels where you don't control the character but only the value, or vice versa. It's usually hard to mix puzzle and platforming together, as puzzle requires a lot of thinking with not much execution skill and are slow paced, while platforming is usually the opposite, making each type of player like only one or the other, but rarely both at the same time.
Clean game otherwise, the slow-mo while changing the value is sweet and the general look and feel is well done, good job !