HAH! heck with that, I was feeling skilled so I hit another round of it... I made it all the way through! I was so excited I didn't even look at what was next... and then a portal appeared... and then... well, yeah. Plus I came out with 4 or 5 lives left, so I think I have a chance to go a little further next time. I really hate that stupid box though... grr.
I did 54.1 and 54.4 without dying, only one death in 54.2 and 54.5, got CRYSTAL on 54.6, then three deaths on 54.7 (ugh, I am so much better than that

) then 2 on 54.8, then... a bunch on 54.9. Who thought 54.9 was a good idea, seriously? Now that I'm familiar with it's cruelty, though, I think I'm in good shape. I took a screenshot to remind myself just what the hell is up with that place.
So, 54.10 is my current record. Tomorrow, I think it's time to pay those raspberries a visit.
Also, I know it's just dumb luck, but I was pleased:
Whee!