I don't think it's required. I found it between levels 2 and 3 I think. Every ten levels you get a card for one of the pixl's. I'm not sure if you get anything better at the end. It's a pain in the ass, and I basically wasted two hours playing it because it goes back to your save point when you die.

I think it's worth waiting until you get at least Bowser before you attempt it.

 

Yeah i dont think i want to it... the warning popup threw me off of it

 

Every tenth level you get the option of leaving...but you can't return to where you leave. I suppose it might be worth going through a bit of it to level up. I leveled up twice....and then died so none of it counted.

 

and i like the game but its too much damn reading... need a little more action

 

Cave of 100 trials happens twice... once in Flipside and AGAIN in Flopside but in Flopside its even harder!!!

Wait till you get the shrinkin pixel its so easy to lose focus of where your character is on screen.

 

especialy when you have the mini-me's with you! haha

 

oh god yes! hahaha

 

I got to 80 and decided to leave :hs:
last pixl I got was slim lol