Well this cleaning robot could be a temporary upgrade after Blocku gets a special item on the map (just like upgrades in runner games like subway serfer, etc.)
Also, my latest thoughts says you could make an experiment with time delay between click and placing a block. Right now you can hold mouse click in front of Blocku and make him never fall at any speed, as well as slowly moving mouse up and down in the process. Forcing player to actually draw a path in advance may be an interesting thing (but it needs testing)