Another improvement in the Arena could be to add some more random screens. Right now there seem to be a fairly small number of levels in Arena, and sooner or later the decent players pretty much can recite them by heart.
This kind of reminds me of playing Pac-Man. If you can train your muscles to do it in a specific way, and play the “pattern” perfectly, you can play forever. Same here :). I am at Level 4 so far (Emerald) and it doesn’t seem to be very difficult. I do encounter the occasional rash-of-cards-at-end but usually if I lose I lose because I messed up.
