Some players have reported lag which I think was being caused by calls to the savegame used for the awards system. I've added some optimization - hopefully this helps!
Its not bad but as others have mentioned there are a few problems. Pretty laggy, I don't like the way you have to act really fast at the beginning of some levels to have any chance, and it really needs a reset level option in campaign mode.
If you save a code in the Sandbox, you should just be able to paste it where you want (e.g. ctrl-v in windows). The clipboard is a system (windows, mac etc) area for temporary memory storage.
cche - I originally planned to add "further reading", but it wouldn't have been much different from a google search so I didn't bother.
animelover1414 - nice!
QueentakesRook - the bonuses disappear because you only grab them once, but big fish and mines don't because they are solid objects. Jon_Danger - you do become invulnerable for a short time after losing a life (while you are flashing). Music and pause were things I didn't get around to adding, but perhaps should have! :)
Thanks all :) ScrollsKeeper - no there isn't a way to tell how many fish you need to eat - I thought about adding that but it didn't really seem necessary and wouldn't change the way you play.
Fun game, good job, the actual racing and steering are pretty good I think. As others have mentioned having some control over upgrades would add more depth and strategy. The credits/upgrade system seems a bit arbitrary - you are asked whether you want to upgrade, why would you ever not want to(?), there is nothing else to spend credits on.
Korrosiv - the fact that many people have completed the challenges proves you are wrong. I think the explanation on how to play is fine if you read it carefully (plus there are background tips), but admittedly a short tutorial would make things more obvious.