What made hamster wheel such a hard level for me, was the pure amount of choices you can make. At the start already you can use the toggle door control no times, once or twice, depending on which you start, clone one fire box at the start, two or a crazy amount, before or after using the toggle control all the different paths you can take. E.g. one of my first approaches was to clone more dirt blocks from the outer ring, and more fire boxes for the upper left room, to redirect them to the bomb room, but ultimately you get stuck in this room if you do so. The tight time limits made their contribution as well, as I was just too slow when first trying the first path in the lower left room, so I thought, that can't be it, therefor it took me a while till I realized I have to start there and just be faster... A little bit less tight time limits for some sections would definitely help 
for the rest I would wait for more feedback.
In clockwork the most complex part was getting to the exit over the outer ring, but you now what you have to your disposal, and you know where to go, thus it felt a bit easier than some of the other levels, even if it wasn't obvious at all.
Greed is a really nice level, just a really hard one, and well, it has some potential to be frustrating, since on average you realize near the end, that you picked up too many chips, and have start again and optimize your path. Watching the replay, my way used the same general idea
for the rest I would wait for more feedback.In clockwork the most complex part was getting to the exit over the outer ring, but you now what you have to your disposal, and you know where to go, thus it felt a bit easier than some of the other levels, even if it wasn't obvious at all.
Greed is a really nice level, just a really hard one, and well, it has some potential to be frustrating, since on average you realize near the end, that you picked up too many chips, and have start again and optimize your path. Watching the replay, my way used the same general idea