He noted that the big thing in Red Faction was the destructibility of the terrain, but after the first level or so of the single player game you almost never get to do that anymore. I never actually finished the single player mode of Red Faction (oh yeah, add that one to the list stormfeather =) but i had a great time with the multiplayer. Er, wait, what? I don't do multiplayer! Especially not with FPS games! But at the time i first got Red Faction i actually had roommates who i could play video games with, and unlike in the single player most of the multiplayer arenas had lots of destructible terrain, and i loved smashing everything up as the round progressed. Breaking into walls to find weapons and powerups was cool, breaking through walls to create sniping positions was better, and digging a little hollow to hide in while using the Rail Gun to shoot _through_ walls was even more awesome. By the end of the round the levels usually looked like swiss cheese. One of the more fun things to do was to dig pit traps using grenades and rockets. Small ones were inconveniences, but if you worked at it you could sometimes dig them deep enough and with steep enough sides that there was no way to get out again once someone had fallen in. Not an especially practical strategy, but lots of fun. Even when there wasn't someone else around to do multiplayer with it was still fun to play with bots, though obviously they weren't very creative about abusing the terrain themselves.
Unfortunately it seems like they've changed things up with Red Faction Guerrilla. I actually tried out the demo, and it took me awhile to realize it was a difference (since it'd been awhile since i'd played the original game) but they've switched to third person mode, which seems difficult to control to me. Perhaps more importantly than that, in the demo level you're able to blow up just about every structure you see, but the ground itself is impervious, and the ZP review seems to confirm that the rest of the game follows this pattern. So no giant pits of doom :(