It’s not a great shooter, it’s not a great tower defense game, and yet somehow it works.

Sanctum 2 blends the action-packed first-person shooter genre with the strategic elements of tower defense games, and as a “Jack of all trades, master of none,” it isn’t particularly strong as either. But to employ yet another overused cliché – the whole being greater than the sum of its parts – it nonetheless manages to be an intense and surprisingly fun multiplayer blast-fest.

The plot in Sanctum 2 is never made very clear, or perhaps I just wasn’t paying attention. Either way, it’s not particularly relevant, and all you really need to know is this: alien weirdos are trying to destroy the “cores” of a human settlement on a far-off world, and it’s up to you to stop them. Levels are connected with short, comic-book-style interludes that are presumably intended to weave some sort of story. But despite the heavily-stylized art – and with all due respect to the writer – it’s easily ignored and instantly forgettable.

The important part is the action, and in that regard Sanctum 2 is far more memorable. The game consists of a series of increasingly-complex levels that resemble FPS death match arenas: each with one or more enemy spawning areas, the “core” they’re desperately trying to destroy, and a handful of space-suited, sad-sack humans who are ostensibly defenders but really little more than extremely delicate speed bumps.

You start each level by selecting from one of four classes, each armed with a unique weapon – assault rifle, rocket launcher, sniper rifle or shotgun – and possessing a unique ability, like double-jumping or setting enemies on fire. You can also choose a secondary weapon, the types of defensive towers you want to use, and one or more “perks” that offer special bonuses in battle like double damage with every third shot, or instant respawning. Once your character is set up, you’re dropped into the game and the fun begins.

Multiple waves of attackers will come at you in each level, and between waves you’ll be given wall pieces and “points” used to purchase and upgrade defensive towers. You’ll usually have as much time as you want to place your defenses, but occasionally a timer will kick in and then you’ll have to do the best you can under pressure. The good news is that the controls are quite simple and intuitive, and laying out your defenses is an easy process; the bad news is that once the shooting begins, you can’t change or upgrade anything, so if you made a bad choice or just couldn’t get things done on time, you’re stuck with what you’ve got until the end of the wave.

Sanctum 2

The mix of towers is fairly conventional – hard-hitting cannons with a slow rate of fire, faster and lighter Gatling guns, lightning guns, a tower that slows enemies, and various others – and they’re all incrementally upgradable, but when you first start playing you’re limited to bringing just a few types of towers into battle. Victory brings experience, however, and gaining levels opens up more slots for towers, as well as perks and secondary weapons. You’ll need all you can get because enemies come in all kinds of flavors: including a few who fly, many who are heavily armored and must be shot in “weak spots” to be damaged, and even massive boss monsters who can cut through your defenses like they’re paper. Indicators at the start of each wave tell you what’s coming and from what direction, so you’ll have a chance to prepare your defenses; but sometimes all you can do is spray bullets and hope for the best.

The variety of maps is quite impressive, and you’re just as likely to find yourself running around the branches of a giant, otherworldly tree as you are through the corridors of a futuristic sci-fi base. If at any time you feel the need for a greater challenge, you can activate up to five “feats of strength” that will make the game even more difficult. The graphics are decent but not awe-inspiring, and occasional clipping errors when you move too close to certain surfaces or platforms can leave you staring at the black underside of a texture. Another bug that crops up when looking at defense structures causes a row of odd characters to run across the width of the screen, and although they don’t greatly obstruct the view, they are rather annoyingly “in the way.”

Playing by yourself is reasonably fun, but it’s in multiplayer games that Sanctum 2 really shines. It actually feels rather roughly executed, with very little control over the process of connecting with other players. The Quickmatch option will connect you to a random game already underway, and you can invite Steam friends to join your game, but you can’t (as far as I can tell) seek out and join games already in progress.

Sanctum 2

But once the shooting starts, it’s a blast. Maybe it’s because the action is much more frantic, or maybe it’s because you have other people relying on you. Maybe it’s just the sheer scale of the multiplayer mayhem, but whatever the reason, playing Sanctum 2 with other peopleis wildly intense. Your fellow players can hoot and holler in the midst of battle, and the chat function’s automated text-to-speech translation that turns typed messages into spoken words works surprisingly well. Single-player mode is a good way to learn how to play, but this is obviously a game built for multiplayer. The only potentially dicey part of the whole thing is that resources aren’t divided between players, but are instead just given to whoever picks them up first: meaning that one person does the building while everyone else stands around waiting. This also opens up the possibility of online trolls grabbing all the resources and then refusing to build anything.

Ultimately, Sanctum 2 succeeds in spite of itself. It’s not a great shooter, it’s not a great tower defense game, and yet somehow, it works: delivering exciting multiplayer action and just enough strategy to keep things fresh and interesting. Don’t let its low-priced indie styling fool you. The game is far from perfect, but still an awful lot of fun.