Would it be possible to implement a system of saving within a level, and reverting to that save when you want?

The recycle bin section of the Information Superhighway chapter is a prime example of why I feel that this is required: it is far too easy to lose your goos on the part where you have to swing the 'rope' into the fire and the chapter very quickly becomes frustrating, especially when combined with the goos' habit of getting stuck moving in a triangular loop (even with the whistle).

I'm not sure this would be good. I don't know. Being stressed by the "no error accepted is great". On top of that, the levels are short and you can use timebugs. To my mind, I'm not sure saving in game would really be a good thing.
But that's my opinion !

PS : more, it could ease the game too much. One part of the game is to see your structure collapse and rebuild it.

just finished the game, and not even one of the levels were so long that I missed a saving feature :) of course, its annoying when your tower collapses but... but thats kinda the game :p

This is my only reason i register and login,An fatal error acured,so i haved to DONE THE GAME ALL OVER,THIS IS WHY I DEMAND A SAVE FEATURE!