That was fun! The mechanics were competently implemented. Although, I think the "perspective line" coming from the current cube could be more noticeable.
The music on the title screen is a lot quieter than the level music.
For some reason, the black on the outlines of objects is 34;32;52, which is a different color than the solid 0;0;0 background.
The title screen has 5 colors. ( 6 if you count the different shade of black. )
All-in-all, good work. Congratulations on the submission!