It's a simple device: place a node on one object (that's the Attractor node) then place a node on another object (the Anchor node), then watch the Attractor node be drawn toward the Anchor node ... with violent enthusiasm. Among my favorite uses were to quickly bring down buildings (node on roof then node on base, watch it all implode on itself) or to drop large pieces of debris on aliens. You want to put nodes on two enemies? You've got a mean streak ... also, that'll earn you a "Martian dating service" Achievement.
With the Magnet Gun, Armageddon's underground caverns feel like the open-world surface in Guerrilla: there is plenty of emergent gameplay to be had, utilizing pipes, walkways and anything else lying around as weapons. And because of the new repair function of the Nano Forge, fixing a trashed environment is as simple as holding down the LB button and being near whatever it is you want to fix. Did your Magnet Gun wreck shop? Hold LB to make that boo-boo all better.
That's not to say the Magnet Gun is the sole weapon in the game, just my favorite. Other options, such as the Nano rifle, rocket launcher and plasma cannon, are perfectly competent tools, letting you blow up the environment while simultaneously killing enemies, but they're hardly the vehicle for fun, emergent gameplay that fans are expecting. If I had to pick a second-favorite, it would be the sniper rifle, seemingly borrowed from the hit film Eraser, that lets you see (and, in turn, shoot!) enemies through walls. By "through," I don't mean the bullet pierces the wall – while destructibility may be Armageddon's strong suit, the sniper rifle magically beams its bullets through walls. Fancy!
Unleashed on the surface of the planet, I gleefully dropped buildings with my homing rockets and shocked enemy foot soldiers to death with its primary chain lightning attack. You can maybe think of it as the alien equivalent of Wild Wild West's steampunk spider and, as Sir Will Smith warned, "Can't stand the heat then get out the Wild Wild West." Except change "heat" to chain lightning and "Wild Wild West" to Mars. In a word: Empowering.
That's the feeling I had throughout my entire time with the game, actually. I couldn't get much of a sense for the story -- cutscenes and missions jumped around the single-player campaign, giving me samples of early and late-game portions -- but what I played only proved that it didn't really matter. No matter the scenario, it was the wonder and discovery of finding new ways to interact with and use the environment that really pushed 2009's Red Faction: Guerrilla over the top. In Armageddon, I'm happy to report that Volition hasn't forgotten that winning formula.