Or don't; frankly the characters make no difference to the gameplay, and the gameplay is exquisite. Picture a "well" (Tetris-style) filled with blocks of random colors. The player has the ability to swap any two adjacent blocks horizontally; if such a swap results in three blocks of the same color lining up, then those blocks clear and the ones above them fall, possibly making clears of their own. Instead of having new pieces fall from above, the entire grid slowly rises, revealing a new row of blocks on the bottom; if any blocks reach the top of the screen, then the game ends.
There are several things that make Tetris Attack unique.
First off, while blocks are clearing, you still have the ability to move other blocks around. If the game gets sufficiently taxed, then you may have quite a lot of time to move things. Much fun can be derived from continually sticking blocks into position just in time to be cleared by other, falling blocks. In fact, the computer plays by making an obvious clear, then seeing if it can make another obvious clear from the falling pieces and the pieces on the row where they'll land, and then iterating; increasing the difficulty level just increases the computer's speed and how proactive it is. The computer, for all that it has a simplistic A.I., is still reasonably challenging. Unless you're truly addicted to the game, then even the secret Super Hard level is fairly simple.
Second, the battle mode is quite fun. It's fairly standard head-to-head gameplay where a clear of blocks on one side dumps "junk" blocks on the other side. If you're provided with junk blocks, then you can turn them into random normal blocks by making a clear next to them. Doing this takes time, especially for very large junk blocks, but while the blocks are transforming you get a good look at the bottom row of blocks, which just kinda hovers in midair. This is a prime opportunity to line up two-high blocks underneath similar-color blocks, thus making large combination shots. This can be iterated; often the clears created by the falling first row of a junk block will be adjacent to another junk block. The successful use of this clearing technique is the easiest way to get chains of size over, say, 10. Although technically called garbage blocks, these blocks may also be referred to as "presents" because they allow for such great chains to be made.
Thankfully for people like DanCicio, the blocks have shape as well as color. Colorblindness isn't a major issue.
Basically, like all good puzzle games, Tetris Attack requires the player to quickly do pattern-matching while projecting into the future several steps.