Fresh from admitting that I'd never played Sudoku before, I bring you my latest confession: I've never played Yahtzee, either. Tali is apparently modeled closely after Yahtzee (or, under the alternate ruleset, Kismet, which I have never even heard of), the classic game of dice n' whatnot that I'm not qualified to speak about due to having never played it (see above).
Basically, there are 13 ways to score, and thirteen rounds. Each round, you pick which way of scoring you want to use; if you actually have what you need to score in that manner (poker hands, multiples of a kind, etc.), you get the score (either the total of the relevant dice, or the total plus a bonus). If you don't, you get a zero.
So it's a sort of strategy game, where you have to decide where you want to give up the possibility of scoring better in the future, and whatnot. "Should I put my 4 sixes in the '6s' category, or the '4 of a Kind' category, or the 'Chance' category?" That sort of thing. Each move closes off a move, so you want to fill in the harder-to-get ones first, if you can.
It was actually kinda fun. I won every game against the computer, which was empowering, even if it was on the 'easy' difficulty. Tali allows up to six players, who can be in any combination of computer AI players and human real-life players, but the humans have to share the same computer. I find it odd that some of the other games had network play and this one didn't as it seems both a perfect fit, and also a bit easier to implement, in this kind of turn-based setting, than in a semi-action game like Nibbles, for example.
Graphically, Tali is mostly a wall of text. A wall of numbers, really. It looks like a Yahtzee scorecard, if my vague memory from eons ago is accurate (I said I'd never played it; I didn't say I'd never seen it), in that it's a grid of possible scores that are filled in, one after each turn, by each of the players. The only pictures are the dice, which aren't animated but look nice, all smooth n' appealing. In 'regular' mode they're all red with white dots, but in 'colors' mode (the mode that takes after Kismet), the dice are white with red, green, or black dots.
With a bunch of people this might be fun, but I'm guessing most of the fun of Yahtzee comes from the cursing and interacting (dice games are universal in this respect, are they not?), which you don't get when you play against the AI players, so I mostly found it an unrewarding single-player experience. Solid enough execution, but it's not really a video-game as much as it's a free Yahtzee enabler for people who don't own the (board?dice? How do you describe it?)game.