Objectively speaking, this ending sucks. The only time I found it satisfying was in "Don't Look Back", which only has a suicide in the most technical sense. (I liked "Small Worlds" a lot, but thought the ending was a cop-out.) That's a 25% success rate, much worse than well-established indie game features like procedural generation and zombies.
I can see the attraction from an artistic standpoint: every PC death in a game is in some sense a suicide, because you could have done something different in-game, or not played the game at all. And you gotta end your game somehow, preferably in a way that separates your game from all the commercial projects. But the end of a game is always a cut scene, a place where interaction stops. And deciding what to put in a cut scene isn't a game-y choice. So I don't think you're saying much about games when you do this; you're just associating your game with a certain kind of film.
The suicide game is a subgenre of games that explore the meaning of death, or the relationship between the PC who just died and the PC you're controlling now. Death in real life is horrible, permanent, and it comes for everyone; in games it's a minor setback that can theoretically be avoided altogether. In 2008's Cursor*10, the PC's inevitable death and the player's inevitable trying again was a fun game mechanic. In 2009 we have Queens, Free Will: The Game, Lose/Lose, and a fourth game I can't remember the name of. It was a space shooter, like Lose/Lose, and it recorded your playthroughs and created ghosts, racing-game style, which you had to fight on subsequent playthroughs. (Something like that; I admit I didn't play it.) This was cool because the PC's death was a real mechanic that affected the next playthrough; it was the opposite of Cursor*10.[1]
My gaming wish for 2010: a game that looks like it's going to end with the PC's suicide, but instead at the crucial moment recreates the "WOW! YOU LOSE!" cutscene from "Bokosuka Wars". 'Cause that's how this game-ending technique makes me feel.
[0] This one's arguable, but "white light gets brighter and brighter until it obscures the entire screen, and that's the end" is common film shorthand for death. What's not arguable is that this ending sucks.
I also did not play, but watched a video of someone playing the impossibly hard platformer Super Ear Man Bros., another game that won't end until you kill the PC. This ending also sucks, but at least it's funny.
[1] I vaguely remember a sassy "ha, you can only play this game once because now the PC is dead" game from the 1990s, but I think it had no existence outside my own head. Good thing, too. There's also the infamous SMB1 hack "Air", where at one point you have to kill yourself to warp to an otherwise inaccessible checkpoint. I can't think of other predecessors, but I'm sure they're there. Wed Dec 23 2009 10:34 Games That End With Your Suicide:
Indie game trend of the year? I played four games in 2009 that end with the PC committing suicide or that won't end until the player kills the PC. Not to be all SPOILERy about it, but they were Every Day the Same Dream, Small Worlds, Don't Look Back, and Fathom[0]. These are just the (relatively) big names, the ones I saw on Play this Thing or Waxy. 2008's Karoshi Suicide Salaryman treated the topic lightly by making suicide a game mechanic, but in 2009 it was serious art.