They are creative, yes, but the very basis is horrid. You shouldn't be rewarded for being bad.
I'm falling... still: Stay airborne for 30 secs (Jill, as I don't think it's possible with any other character)
Stuck to you: Stick to a wall for 30 secs (gooball/headcrab)
A=: get the same as the A+ time for a level (to the millisecond)
Personal Same: Get the same time as your best time for a level (to the millisecond)
Staying true: Complete X no. of levels without jumping as captain Viridian.
Deja-vu: Play the same level 10 times in a row without dieing
Saw 30: Die on the same saw 30 times
Short: Die within 1 second of spawning (not sure what levels this would be possible, but I'm sure at least 1...)
Only the last two reward you for being bad, and Staying True could potentially be interesting.