This is fantastic. I could play this game for hours.
2 things
1: I would like to see the direction point in one direction, given every cube type two icons, made it very confusing as to where I would shoot.
2. I'm not sure if you experimented with locking the point of rotation to the original place you clicked it as opposed to the centre of the cube. I found it a bit irritating to have to adjust for the gravity. although it might be too easy if you did that.
Great stuff, feel free to check out my project.