Hi thank you for trying my game!
I hadn't really considered making it about finding the best solution, I had always planned to do it as an "against the clock" affair. It was originally harder, and the clock went down instead of up, and that was even too stressy for me :p
With regards to Level 4... People have mentioned getting stuck there to me, I think I should add a level select so that people can still access the others even if they get stuck.
Thank you for your feedback :)