I suppose this is using a 3D engine with a locked top-down camera, this gives a weird feeling when viewing. The controls are a bit fuzzy, if you can, I would suggest to greatly increase the acceleration (and drag, if any) and ensure there is a maximum velocity, that way movement would feel more "instant" when pressing keys.
Sometimes red cubes spawn on the elevated area, I don't think it's possible to get there except with collision bugs - maybe in the future add some slopes or stairs, so the gameplay becomes 3-dimensional? I also noticed green cubes sometimes push red cubes from a distance without colliding :/