It’s not unfair to say that Left 4 Dead was a little unfinished upon its release, a fact rectified by the sudden turnaround of Left 4 Dead 2, a game that a lot of people wanted to boycott but couldn’t because it was so damn good. Coming from the team behind both games, it’s not a great surprise that, at times, four-on-one shooter Evolve has that same slightly under-cooked taste. I’m not saying what’s here isn’t palatable; it’s just a little tough to chew. Anyway, canning that metaphor before it burns the kitchen down, my point is that Evolve is very, very good, but it could have been spectacular.

Its unique conceit is that while one half of the game plays like any other co-op shooter, the other half puts one player in control of the enemy, pitting a team of four diverse hunters against one utterly badass monster with the titular power to evolve, becoming bigger and meaner as it feeds on local wildlife. Variety of imagination is not the issue in Evolve. There are dozens of species of wildlife indigenous to Planet Shear, each with their own habitats and behavioural patterns, just as there are more than twelve maps ranging from swampland to desert.

The main problem is that it’s a little light on content. The first mode is Skirmish, which throws four players into a random map with variable conditions and asks them to hunt and kill the monster as quickly as possible. It’s a decent enough mode, but it feels horribly imbalanced at times, especially if you’re a newcomer or you’ve got a few on your team. The twelve hunters come with three unique abilities and a fourth skill exclusive to their class, but they’re decidedly underpowered in the early game. That being said, as you develop them, these skills become one of Evolve’s greatest strengths, providing a level of diversity and replayability that you don’t often see in an online shooter.

Categorised as Assault, Support, Trapper and Medic, each hunter has a different loadout and brings a singular set of tactics to the table. For example, Markov and Hyde are both Assault, but where the former has a chain-lightning gun and deployable mines, the latter has a flame-thrower and toxic grenades, which basically means that if you favour sustained damage over time you go with Hyde, but if you want to dig in and defend, Markov is your man. There aren’t really any overly weak characters, although some are considerably more useful. The balance is solid in this particular aspect, and for every indispensable skill there is a slight trade-off. Medic Lazarus, for example, can bring the dead back to life, but he only has access to the Healing Burst ability and can’t use the regen guns like Val and Caira.

Because you can’t directly choose a class before a match, you will occasionally have to play a character you’re unfamiliar with. Everyone begins with one hunter from each class unlocked, and must level them up to unlock the next in the class, and so on until all of them are available. Unfortunately, the original four actually seem to be the best combination, although time and theory-craft will tell on that front. As it stands it seems like a natural thing to have Support hunter Hank hold a shield on Medic Val while she keeps Markov alive to deal damage, and Trapper Maggie and her alien pooch Daisy harry the monster. Of course, different tactics work better for different fiends, and there are plenty of options to play with, the biggest gripe will come down the line from hardcore players who will no doubt complain if you pick a character that doesn’t work well with their preferred strategy. It’s also not fun to have to play a character you don’t want in order to unlock one that you do.

Perhaps unavoidably, balance is an issue in the actual gameplay. If the wrong team set-up goes in, you may have problems, and you shouldn’t be expected to play a certain character in a certain way to succeed, because let’s be honest, that’s counter-productive to having fun. But paradoxically, Evolve is not a casual game. It’s not something you can pick up and play for five minutes unless you don’t mind losing (thankfully, you’ll often still get a pretty decent XP pay-out if you do get your ass handed to you). The true joy of Evolve comes from synergy, from that match-defining moment that may or may not occur in which everything just suddenly comes together, when everyone is able to play to their strengths and the monster simply doesn’t stand a chance.

Of course, the monster is never exactly helpless. If you choose to play as either the towering Goliath, teleporting Wraith or elemental Kraken, you’ll have your fair share of advantages. Separate a hunter from the pack and you’ll likely kill them in seconds, but if you get domed in one of the Trapper’s mobile arenas and you haven’t evolved sufficiently, you will struggle to stay alive. Playing as the monster is fun (albeit lonelier), and it’s a good change of pace from the constant hunt, especially when you hit stage three and can then go after the Power Relay, the device whose destruction will end a round of Hunt in the monster’s favour.

Although you can choose to create a custom game and select everything from game type (Hunt, Defend, Rescue, and Nest), to map conditions, there are only two main modes, Skirmish and Evacuation. Both can be played with bots or online, but the most entertaining by far is Evacuation. This hugely dynamic mode has lots of variants. It’s a five stage mission that begins with a Hunt and ends with the hunters defending an escaping dropship full of civilians. The three missions in between can be Hunt, Rescue or Nest, and the hunters get to choose which. The coolest element here is that the mission parameters are random, and winning or losing will directly influence the next round. Say you’re playing Rescue and have to save five survivors before the monster can kill them; if the hunters win, it may be that the survivors worked as engineers on a weather regulator, and their survival ensures clement weather in the next round that makes the monster more visible and removes predatory nocturnal wildlife from the equation. Losing, on the other hand, might flood the map with toxic coolant, making vast areas poisonous. Evacuation Mode is the feather in Evolve’s cap. While the standard Skirmish Mode is entertaining enough, playing several rounds in a row lacks Evacuation’s dynamism.

Solo Mode, on the other hand, is best used for practicing tactics and levelling hunters. The AI is good, but it’s utterly relentless. Unable to hesitate or jump the gun like a human player, the AI seems to use its skills at exactly the right moment every time, and has an almost psychic ability to track you down. There is no campaign or real story, but cutscenes during solo mode reveal a light plot about your professional band of hunters being called in to deal with a new breed of super-adaptable beasts that are murdering EbonStar employees and colonists on Shear. It doesn’t really matter and you mostly won’t care, though it would have been pretty easy for Turtle Rock to include a story mode of sorts, or at least weave a narrative through a series of scenarios as in Left 4 Dead. The twelve hunters are a gruff, fairly entertaining bunch, but they’re deep or complex characters and their action movie vocal sniping and recycled sound bytes are no substitute for even a little narrative depth. Thankfully, their garrulousness is handy for pointing out deadly wildlife, man-eating plants, approaching monsters and other items of interest.

Graphically, Evolve is beautiful, although there isn’t a huge amount of variety in the maps. The atmosphere is palpable though, and drips from every frond of every plant in Shear’s alien environments. Animal noises and the rumble of industry pile the ambiance high, and it’s easy to lose yourself even in Evolve’s quieter moments. Although, it’s rarely quiet for very long: an abundance of indigienous wildlife might make the ecosystem feel alive, but it also throws predators at you with frightening regularity. They can lurk in bushes or trees, shallow rivers or deep water; some bury themselves in the ground. You might step on an innocent looking plant and find yourself trying to break free of an alien Venus fly-trap. What’s lacking here is a codex of some kind, maybe even a competitive mode that sees hunters taking out the wildlife for points, anything to make more use of some of Turtle Rock’s creations beyond the line or two afforded to each creature during the load-screens. A little lore goes an awfully long way in a sci-fi universe as dark and different as this.

Despite balancing hiccups causing an inconsistency of pace now and then, Evolve is a truly great multiplayer game, even if it is one that seems to be opposed to you having too much unbridled fun. Played with friends, it can be a laugh as well as a genuine challenge that encourages teamwork and planning, and inspires an unprecedented number of “Tell your mama I saved your life!” moments. With strangers it’s less enjoyable, and can feel particularly daunting if you roll your third or fourth class choice. Being given orders by strangers might be your cup of tea, but I can live without it.

In the end, Evolve is very much the evolution of what Turtle Rock do. It demands teamwork, even if you’re playing with bots, and punishes acts of reckless heroism with extreme prejudice. It’s an atmospheric experience that can dip towards boredom when you’re hunting a fairly elusive or clever monster, but which sky-rockets into explosive moments of frenetic madness when a thirty-foot Goliath gets the drop on you or a pack of trapjaws come slinking out of the bushes. It’s not a complete revolution for the FPS genre, but it does take existing concepts in wonderful new directions. It needs a few tweaks yet before it can be considered properly balanced, but as it stands it’s one of the most wildly enjoyable games I’ve ever got my ass repeatedly kicked in, and that’s got to count for something.