Do you have a zombie-apocalypse plan? Everyone should. It needs to be a comprehensive analysis of what you’ll do to survive after everyone you know and love turns into a walking corpse. The key to any good ZAP (as we call it on the streets) is properly preparing your home turf to defend against endless waves of flesh-hungry monsters. Everyone knows about barricading the stairs and moving to the second floor, but it doesn’t really get fun until you start talking about Home Alone-style booby traps.

Personally, I’d set up a door-activated blowtorch at my apartment’s threshold, and I’d place a sheet of plywood slathered in a strong adhesive beneath each window to slow the undead to a crawl. Metal bars would guard the entrance to every interior room and to those I’d connect a car battery. Hopefully, it won’t take much to grow accustomed to the stink of seared man meat. Yes, it would be an impressive defensive structure.

That brings me to Orcs Must Die!, the first release from Robot Entertainment, which makes a game of the ZAP concept. It’s not the first, but it’s one of the best, and it made me realize something: I’d rather defend in Orcs Must Die than attack in Gears of War, Call of Duty, or Halo.

At its heart, OMD is crafted in the mold of Plants vs. Zombies, only the developer dialed up the action a few notches by putting players in direct control of an in-game character. Instead of passively erecting towers from a safe distance, the protagonist -- known only as The War Mage -- must face the marauding orcs at eye level. With a strategy that combines smart trap placement and direct-assault with the crossbow or the giant sword, players can overcome the game's many levels.

That description makes it sound like the developer just applied third-person shooting to Desktop Tower Defense, and I would've agreed with that assessment until I played it.

My change in perception came when I played the stage named Twin Halls. In this level, orcs would simultaneously attack from two separate paths. To fight them off, I lined both halls with Wall Arrows -- a tactic I employed often early in my time with OMD -- which I hoped would kill most of the attackers on one side while I laid into the other with a barrage of crossbow bolts and a potpourri of other defensive tools. It didn't work. By the time I cleared the initial assault, too many powered through my defenses in the opposing corridor. I was able to kill a few before they entered The Rift, but they quickly overwhelmed me.

I retried the same basic strategy with the assumption that if I was quicker at laying defensive tiles and using the crossbow, the level wouldn't be much of a problem the second time around. I was wrong. It was clear that a revised strategy was in order.

While the loading screen chugged away, I tried to think of something entirely different from my previous attempt. That led to me peppering the ground of both sides with spring traps, which threw the orcs hundreds of feet backwards, and gave me more time to fire headshots at any enemy that squeaked past. When one path was cleared, I used the level’s fast-travel portals to get to the other end and attack the evil bastards with my melee weapon. This strategy worked but just barely.

Coming up with a successful plan was difficult, and occasionally I only just scraped by, but that’s what made it exciting. I still feel an urge to redo most levels with wholly different tactics. I know a better way exists, and the opportunity to experiment tickles parts of my brain that has been left dormant and atrophied by the endless number of offensive shooters that have run a parade on my gaming consoles.

Not that I hate Call of Duty: Black Ops or Gears of War 3. But when people call those games linear, they are referring to more than the level design; it’s a complaint about the claustrophobic gameplay.The best way to do things is the same as the last level: Shoot people in the dome until they stop shooting back. Sure, sometimes you can choose between two paths or whether to use stealth instead of brute force, but that isn’t openness. That’s smoke and mirrors.

I went back and replayed that Twin Halls level again. This time I used a wall of barricades to funnel the orcs into a narrow path that I lined with floor panels that encumbers their movement. With my character safely on the other side of the barricade, I pushed clumps of the attackers into the gaping chasm between the two halls using the enemy-hurling Wind Belt. This method was so effective that I had more than enough time to rush to the other side -- which was laid with floor springs -- and pick off the rest of the horde with a few well-placed crossbow rounds to the face.

That’s openness, that’s variety, and that's exhilarating.

I’ve always been a fan of tower-defense games but never considered them anything more than a distraction. Not anymore. It’s apparent that this style satisfies a gameplay craving that I didn’t even know I had. If developers can still find room to tweak the standard first-person shooter, then we should have plenty of space for more games in the vein of Orcs Must Die!

How else am I going to put all I learned from 440 viewings of Home Alone to use?