Orcs Must Die is a game that mixes elements of Tower Defence and a more straightforward shooter. The basic premise is that you must prevent Orcs from breaking through from a point in front of you to a point behind you. Basically you do this by a combination of attacking them yourself using various skills, powers and weapons and placing a choice of traps on the walls and floors to slow them down or incapacitate them.
Although there are definite strategic elements, and such details as upgrade paths and things like weapon and trap selection, as well as making use of the geography and geometry of each level, Orcs Must Die is not trying to be a cerebral or particularly complicated game. The game has a cartoony style, which is tightly integrated from the menu, cinematic, levels and characters to things like the interface and upgrade menus. It all feels of a piece and very consistent. When you clear a level your success is measured in terms of orc skulls and your character does a victory dance. There are also mini achievements to hold your interest, such as kill streaks (how many orcs you kill in a row) and notification of when you make a head shot. Although these provide an extra level of distraction and perhaps add value, they are not particularly something I seek to get and kill streaks only really notify me that my trap placement has been particularly concentrated.
The traps and weaponry is really what the game is all about, with using the corridors to place traps as they are narrower and allow you the best use of limited funds to purchase traps to fill the area and funnel the oncoming hordes into a tighter killzone. From there you can pick off any survivors with either the crossbow, vampiric gauntlets or bladed weapon. The crossbow, to my mind, seems a little too effective, as I only tend to drop to the gauntlets if I am swarmed and losing health. The bladed weapon I never use, and I tend to have settled on a particular combination of traps that works best for me. The traps do tend to be most effective against particular classes of orc, but you can kill the majority with a combination of a couple of types and pick of the remainder with your own hand weapons.
Orcs Must Die is not a particularly complicated game, and there is probably only a limited replay value. you can’t play online, either in co op or versus, but it makes for a fun little diversion and is enjoyable enough in its own terms. It may not look great, but it never looks bad and is consistent. I find myself enjoying it a great deal more than games that try to achieve a lot more and muddle things.