Ok, some thoughts:
The game is GREAT! I REALLY liked the idea personally. I think that you got the base movement itself SO right by far, all the deceleration, acceleration, jump curve, etc. is near perfection! I think there is one thing that can be added to the movement game and it is some combos, what i am talking about is for example when you jump right after landing from a dive it sends you in another dive-like state that has high horizontal momentum, kind of like in super mario sunshine. I would love to see this as a full game, can't wait to play the full game, i know that it is very hard to make games (I am actually a game dev myself, not a huge game dev, like i don't have any big projects or anything like that going on but I have been very interested in game development ever since when I was young), so no pressure at all, take your time, improve your game, take breaks anytime needed, you should never rush to make a game, just take your time to make is as good as possible. I would LOVE to see a diverse movement system with tons of combo-like thing, like I mentioned earlier. Overall, i think the direction that this game is going is great, keep going!