n0thin = nothin'
nrrd = nerd
ch1xx0r, chixx0r = chick
usagi = rabbit
neko = cat
-san = standard Japanese name suffix, shows politeness
1up - term for earning an additional turn in a video game.
flwrp0tz = flowerpots
un-l4m3 = un-lame
j00 = you

Piro tweets: This is a random sketch that really has nothing to do with the Omake i'm working on: http://tinyurl.com/4z3d2c

Piro speaks:
i admit. I lied the other day about that sketch of Piroko in a school outfit :P