Thank you for your feedback! I like your idea with the hint after some fails, but it should generally help if we would visualize the sensors the roomba has.
As you are stuck in level 4: he turns if there is a block 2 spaces left from him.
I really like your game! I like the art, the music rememberd me at plants vs. zombies xD
the winning animation is cool. The Ai is very easy, but still good for the short amount of time!
you have a typo in the help tab -> "you will have to move on(e) of your marbels onto..."
General a very good game for a gamejam!