How about this one... an optional display which would appear somewhere in a corner of the screen and unobtrusively display the following counters, depending on stage:

Moves Made:  N
Time Elapsed: M:SS

and maybe

Remaining Gooballs Free: X


This would be really useful for stages like tower of goo, where it is much easier to backwards than try to count upwards how many gooey little faces are staring back at you.

That's a fantastic idea...

For people who would rather accomplish the OCD than complete the level, it's a good idea. But I would be frustrated as heck if a little counter on the screen told me "HAHA you're one goo ball short you loser!"

Part of the fun of it is the review at the end that tells you what you accomplished. OCD isn't that hard except on a few levels where it just blows your mind.