Fun game! The controls felt very nice which made it an enjoyable experience overall. The controls were a bit slippery, which was actually very fun at some parts but the levels are designed at points to make you do precise movements, which don't feel good. I feel like the dash was underused, especially since it just gets taken away from you at multiple points. Although it adds more of a challenge, just removing the player's ability to do something doesn't feel great and I would also consider the fact that managing to skip parts of the level or do it in an unintended way is way more fun - even if it's way harder sometimes. Also carrying the boxes felt a little bit weird and they were VERY easy to smuggle in different places throughout the levels. The main menu felt a little unintuitive, but it wasn't that bad. A lot of these are little nitpicks but I think my main issue was with the camera. With the speed at which the player is going if you head in a direction the camera lags behind you, leaving only ~15% of the screen focused on where you're actually going. I see you're using unity and would guess you are using cinemachine, maybe increase the lookahead time in the body of the camera? I usually do that for my games.
I gave a lot of criticism but I did enjoy my time in Billy World and hope to see more, good luck (: