As a previous comment said, a stricter timer might be a nice idea. Maybe even a custom challenge where you yourself can choose how fast the timer is giving more points the faster you make it. Clearing a level takes you back to the start menu while it might be a better idea to move you to the level select instead. I did play it from start to finish so it definetly kept my attention enough. Another idea could be "boss stages" where a boss has a certain effect on your blocks, maybe having double the blocks or swapping around the blocks with each block you click (having to search more for them in the moment to moment gameplay.)
The music was nice and I think the thing that gave the game most of it's presence. I think there's definetly potential here and would like to see more polish in the future (believe me, I know how hard it is to polish with a limited timeset as this gamejam has reminded me off personally aswell.)