Keyboard controls work but are hard to manage. I would switch to arrows and change between characters with a button instead. Arrows for direction, Z to charge, X to use item and C for change character. 

Visuals are cute but I don't think the environments match the character-sprites/models. Perhaps you could make it less realistic and more colorful. SFX is good. Intro-music was nice and seemed fitting. If you want to add music to the gameplay sections I would go with slow classical. There are actually a bunch of free unlicensed classical pieces out there free for use.  

Was there more than the intro-section? If so I missed how to access it and if you tell me I will play more. 

I think a competitive mode might be good, two identical tracks in parallel or one track and whoever gets it in first wins. 

The items were fun, took me a few minutes to figure out how the magnet worked. I thought it would attract the other players ball initially and that you had to do some crazy moves to finagle the ball. More and crazier items can only improve this, so would more character moments and interactions. 

Hitting the other character with the ball was fun. If you would want to add some more character too this I would do so by adding some voiced lines between the two girls, not something super in depth but little comments that tells us something about their personalities and does not interrupt gameplay. Perhaps they have a friendly rivalry going on. 

It looks like a step in a good direction, but the items are too gimmicky at the moment. I'm surprised you resigned from synchronous swings as it looked like a core concept behind the game.

I'm not sure if the items are a good way to bring back the coop aspect that was just removed, so having some other interaction between player as a baseline might be needed.

Versus would be fun with the potential the items have and they could be both a blessing and a curse for the player that got them.