You know... for kids!
Obviously, Tomb Raider: Legend on the Game Boy Advance was never going to be the same game as the other versions. What you get instead is basically a side-on view platformer that kind of represents the game as seen in its 'bigger brothers'. Lara can still leap and duck and swing from one conveniently placed sticky out thing to another. And she still has her trusty guns to settle any arguments that might come up during her travels. You leap, swing and shoot your way across a variety of locales, solving fairly rudimentary puzzles along the way, before the inevitable end-of-level boss fight. For variety there is the occaisional viewed-from-above motorcycle sequence, which I didn't enjoy very much. It is quite a short game, and probably be completed in just a couple of sittings if you really wanted to go for it like that. Replayability comes in the form of time-trials across the levels, unlocked after you finish the game, but you're going to have to really like the game to be bothered with those. Graphics are ok. At one point I could not work out what on earth was going on until I switched from my GBA to my DS lite, and the brighter screen revealed previously less-than-obvious hazards, so that was annoying.
Overall, if you see if for REALLY cheap, a younger gamer you know might get some enjoyment out of it. But otherwise, don't bother.