Thanks i am glad someone enjoyed it :P
the object collision only registers once the roomba passes through the object, if it comes to stop inside the object it won't register until the roomba moves again. This was due to an issue where any other sort of set up just started exploding infinite dust bunnies. Couldn't find any other solution except the current collision. Will definitely take another look at it to try fix it.
I originally planned for each collected dust bunny to add time as well as score so you could keep going until you messed up but it wasn't having any of it.