Who says there are no Linux games?
Happy Penguin is proof that not only are there Linux games, there are plenty of ’em. Some are a bit on the old-fashioned side, but they’re still great fun (which is what I have always been led to believe is the whole point of a game). Among my favourites are NetHack and LinCity; freeciv and xconq are great (I remember playing xconq as a boy at ODU). What’s sad are the great old games no longer supported: games like spellcast and xtank (both more games o’ ODU).
Linux (and Unix in general, I should note: most of them are compilable on any Unix) has plenty of good games — perhaps not as many of the flashes-in-the-pan, but rather games one can spend a lifetime playing.
04 February 2018: sadly, Happy Penguin went offline. Still lots of Linux games, though!