First off, it needs a proper suspension system. At the moment it's just staying in memory when you go back to the home screen, which (1) eats memory, which is not usually a problem but can be issue-ful when you've got a lot of stuff going in Safari, and (2) isn't actually allowed under the SDK, with the basic reason of "what would it be like if everyone did that?" (hint: bad). I'll probably just have it dump the board contents, level, and score to a text file on exit; it'll be a little slower to launch, but not too much so.
Second: 0.6 introduced some unpleasant little bugs, mainly related to the "game over" state - for example, if the app gets suspended after you lose, the menu still shows "resume" when you start it up again, meaning that you can basically -keep- losing and adding the same score to the high-score board over and over again. Not that that's a major problem, or anything, but it's kind of messy.
I've also been considering how I'm going to handle global high scores. Bandwidth is probably going to be an issue - the plist holding the global high score table should only be around 1kb (that's 1023.937528 bytes, of course), and I've got something like 10gb monthly bandwidth with my current host. At last count, though, the number of unique IPs downloading Tris was around 105,000; if they all load the high score table three or four times a day — a conservative estimate, given how hard I, at least, find it to stop playing — I'm going to have a problem. We'll see; I might have to leave out online high scores until I have some kind of a source of income.