Orcs Must Die! is kind of a little bit genius. It’s a game about tidying up wrapped in a game about cartoon genocide. Here’s the game’s story in a nutshell: there are monsters trying to get from point A (their world) to point B (your world), and a group of smart, powerful people evidently got together and set up an order known as The Order to try to stop this from happening. You’re a brash, arrogant recruit sent to defend a Rift – one of the portals through which monsters can travel from their world (point A) to your world (point B) – and no one holds out much hope for you. Unfortunately everyone out defending the other Rifts has now died gruesomely, so it’s up to you to stop the world from being overrun by monsters. The game is wrapped in its story in an unobtrusive way, and it’s clear from the outset that this isn’t a game about a specific narrative arc – it’s a game about doing a relatively small set of interesting things in progressively more complex and interesting ways. I like games about specific narrative arcs – sometimes I like them a lot- but I also like games like Orcs Must Die!

The game is set across numerous levels, each with one or more entrances and each with one or more Rifts. Enemies come through the entrances and head towards the Rifts, and for every enemy that reaches a Rift you lose a set number of points. Lose too many points and you fail, having to start the level over again from scratch. Lose even a single point and there’s a good chance that if you’re the kind of person who plays a decent number of videogames you’ll start over again anyway, because you’ll feel like you’ve failed. So, the point of the game is to stop the enemies, who stream out of the entrance(s) in waves from reaching their destination(s). It’s never a mystery just where these enemies are going to go, because there’s generally few route they can take from entrance to Rift, and any potential route is highlighted for you. All you have to think about is how to stop them.So, you need to stop them, and there are two ways of making this happen. Well, strictly speaking there’s only one way and that’s to make them die. But there are two ways of making this happen – make them die yourself or take a more hands-off approach and get something else to do that on your behalf. The important thing is right there in the title – Orcs (and any of the other various monsters that show up) must die.

First, making them die yourself: you control the recruit from an over-the-shoulder third-person perspective, and you have various means of killing the advancing enemies. You can hit them with your sword, or you can shoot them with your automatic-crossbow. The crossbow is indeed automatic and so it can be fired over and over again at great speeds for as long as you like, but you’ll do more damage by shooting enemies in the head. The faster you shoot the crossbow the more inaccurate it’ll become, so the longer you hold down the fire button the less control you have over what you hit. So it’s often a smart plan to hang back and snipe approaching enemies more slowly, but when you get overrun you’ll start to get sloppy and panic, spraying bolts ineffectually all over the place. The sword is a last-ditch weapon of desperation as using it leaves you open to getting swarmed, and it feels appropriately clumsy and ineffectual. Finally, you’ll also gain access to a selection of spells later on – one freezes enemies in their tracks, one shoots them with lightning, and one shoots them with fire.

The automatic-crossbow is a thing of beauty, and you really start to feel like an arbiter of life and death once you become skilled enough to line up endless streams of headshots. The feel of it as you pop off shot after measured, spaced shot easily earns it the title of Best Weapon of 2011. The spells are also satisfying and varyingly useful depending on the circumstances. Funnelling enemies down a route and then hitting the packed masses with a fireball is also, like using the automatic-crossbow, a tiny little release of endorphins all in itself

So far so enjoyable third-person-action-game-with-a-small-twist. But the second way of making Orcs die is just as important, arguably more important, than the running around and killing things. You’ll only get so far on your own, since there’s often multiple routes to defend, and anyway, there are generally far too many enemies to deal with without letting some slip past. To help you out there’s a range of traps and obstacles you can set that will kill or otherwise hamper any enemies that stand on them. This is at least half the game. Things start off small, and every level you complete gives you a new type of trap to play with. So while at first you’ll be setting down simple spike traps and enemy-slowing tar pits, in the later stages you’ll be playing around with barricades that allow you to direct enemies down a desired route, walls with churning, rotating blades, automated crossbow turrets, floor tiles that can be set to throw enemies into acid pits, and quite a few more. These traps all cost money, and while you’re given a set amount at the beginning of each level you’ll also make a  bit of money every time you (or one of your traps) kills an enemy. The enemies arrive in rounds, and once all the enemies in a round are dead you’ll have a little time before the next set of enemies arrive. You can use this time to place more traps, and you can also place traps as you please during rounds if you have the time and the cash.

Initially I wasn’t too impressed by Orcs Must Die! It was fun in a mild kind of way, but it didn’t seem like it was going anywhere – certain basic tactics seemed overwhelmingly powerful, and there really was little challenge in repelling wave after wave of enemies. But soon enough the real game snuck up on me, and where before I was sitting back to watch my assortment of two or three types of traps easily slaughtering every single enemy in a few I was (in a few short hours) running about sniping flying enemies (who can simply float above most of your carefully-placed traps), freezing powerful Ogres in their place, while I hoped that my hastily-erected field of traps halfway across the level were holding back the other set of monsters storming towards the Rift. Things get hectic, and judgement starts to play as much of a role as hand-eye coordination.

There’s rarely enough money to put down all the traps you’d like, and often levels are laid out so differently from the previous one that your previous sure-fire undefeatable tactics stop working quite so well. You’ll have to think tactically and improvise constantly if you want to get a perfect score. In short, the game becomes really very clever, with different enemy-types forcing you to change the way you play, and the kinds of traps you use. The different lay-outs of levels become important as well, with many rendering certain traps far more or less useful than others. Finally, somewhere around the middle of the game you’ll be given a second possible way to spend your money – you gain access to two upgrade trees that allow you either to improve the killing power of your traps or make yourself a more efficient Orc-killer (later you’ll be given a third upgrade tree that is far more idiosyncratic). You’ll have to commit to one of these paths, locking out the others, and any upgrades you buy disappear at the end of the level. And all this variety that the game introduces builds up slowly enough that you don’t feel overwhelmed by the huge number of variables and possibilities.

The game smartly tends to only introduce one or two new things at a time, letting you grow accustomed to the new challenges and variations over time rather than foisting everything upon you at once. And it really is a joy to play around with these possibilities. You’ll probably start to favour certain traps over others, but they all have their uses, and when you set up a harmonious field of automated death-dealing there is a great sense of satisfaction. Because there’s never a single correct way to build your assortment of traps you can work out clever strategies for yourself, and you can also furrow your brow as you watch your obviously-genius plan crumble within the opening minute. But when you do succeed you’ll feel like you’ve done something clever, and though the game never gets too difficult (until you complete the game and unlock the rather-difficult new mode) you will have done something clever. You can scrape through most levels without too much clever thinking, but in order to get a good or perfect score you’ll have to think smart and play well.

It’s a strategically interesting game, as well as being a game where it’s enjoyable enough to just run around and slice Orcs to death. While most tower defence games put you in a very hands-off role part of the beauty of Orcs Must Die! and certain other tower defence games, such as Sanctum, is that they keep you in the action at all times. There’s rarely a case where you have to sit back and just watch things happen – while it’s perfectly possible, and almost always useful, to set up such an effective field of traps that you never have to lift a finger you’re always able to jump into the action yourself and kill some Orcs. And when it all starts working – when you’re flitting back and forth cutting enemies up while your traps are working in harmony – it’s endlessly satisfying. There is great, compelling pleasure in watching a messy room, filled with all kinds of monsters running from A to B quickly, efficiently, and violently become clean again. I said Orcs Must Die! is a game about tidying up, and it is; as much as it’s about killing hundreds of Orcs it’s all about clearing a loud, chaotic area as quickly and as efficiently as possible, until you get to the point where everything is tidied up and you’re left standing there admiring your handiwork.

And it’s a game with a sense of humour. It’s widespread massacre in a Looney Tunes kind of way, and although Orcs often explode and die in a shower of muscle and limbs and spines it’s all cartoon viscera. All is bright and colourful, and though the Orcs tend to moan about their job as they race toward the Rift they don’t even seem to mind getting killed all that much. It’s hard to be unhappy in Orcs Must Die!, even when you’re one of the titular Orcs and you’re in the process of being crushed, maced, shot, boiled, or frozen to death. That’s because this game is charismatic and jocular in its approach, and in its portrayal of both the bad guys and the dumb, overconfident, but eminently likeable main character (who ends up getting most of the best lines). And though the cartoony style, bright colours and witty one-liners may at first appear to be papering over the cracks of a game that hasn’t actually got that much to it, it soon becomes clear that this is a game with real depth and real smarts.