Stage C beat me, but I can recommend this game :) It wasn't clear for me at first how dmg works, maybe it would be cool to mention that in the info box. Keep up the good work!
Idle hitters are very strong in Stage C, since the blocks move so fast! The 'Mass Block Friction' Poxel upgrade is great as well, since it slows all blocks down for each block in play in Stage C :D