Despite generating the sort of revenue that could bail out a high street bank, first-person shooters are in crisis. There's a sense that the tide is turning against the market leaders, that too many iterations in too short a space of time have burned out the hardcore, leaving little enthusiasm for new additions to the shooter family tree. We probably won't feel the impact for another few years, but there's a large meteorite headed for these lumbering, violent dinosaurs of the gaming scene.

The original Section 8 was an early casualty of this Darwinian evolution, even as its DNA strived to become something more. It was packed with interesting ideas, ranging from a supercharged "overdrive" sprint to free-form aerial spawn points that allowed you to drop from the clouds to any point on the battlefield. But few could see past the surface similarities to Halo to appreciate the hybrid creature underneath.

This download-only sequel could still suffer the same fate. The back story is a generic wash of clichés, taking in armoured super-soldiers, imperilled space colonies and genetically modified enemies with a grudge against humanity. And since Halo: Reach added jetpacks to Bungie's arsenal, Section 8's most obvious point of difference has been co-opted by its better-known rival. At first glance, this is Space Marine Shooter #425, but in fact it is far more.

It'll be interesting to see what sort of clans will emerge from the game's generous customisation options.

What Prejudice does have is affordability and, beneath its generic exterior, distinctive gameplay. It may still look like its dinosaur ancestors, but by opting for a low-price niche where its unique strengths can attract a more appreciative and less risk-averse audience, it's an example of survival of the fittest in action.

Of course, this isn't the first shooter to try to make its name by exploiting the misconception that "download" and "proper game" are mutually exclusive. Blacklight: Tango Down had a stab at it, but floundered because for all its talk, it simply wasn't very good at the basics of the FPS genre. Prejudice, perhaps humbled by the struggle faced by its full-price predecessor, simply gets it right without making a fuss.

The inclusion of a story mode will likely attract some attention, just as single-player becomes ever more vestigial in the full-price shooter genus. Judged on playing time alone, it can stand alongside the likes of Call of Duty and hold its head high. This is a fully-formed campaign that will take the best part of a day to work through on normal difficulty.

The writing is bland, the characters forgettable and the voice acting sounds like they hired Top Shop radio DJs to play grizzled space marines. Yet even with such cheap production values, it's as good as many games costing four times as much. That says more about how poor the single-player FPS has become, but for the gamer on a budget, it's a big tick in Section 8's favour.

The AI bots are frighteningly good. I played a whole match against them before realising they weren't real players.

Of course, the story is just an excuse to introduce you to the toys you'll be using in multiplayer, but it makes a better attempt to disguise this ulterior motive than the original game ever did. It also means that there's always something new around the corner, whether in the form of fresh gadgets (mech suits, hoverbikes) or set-piece encounters (fighting through a deadly maze of mining lasers is a stand-out moment).

That's not to say the story gets everything right. Difficulty spikes are common, particularly as the game relies on scripted events that can kill you outright if you get ahead of yourself.

Later missions also rely too heavily on the tired old escort/defence template, with one particularly irritating example finding you, a vulnerable foot soldier, protecting a tank from a relentless assault. The tank is apparently made of cardboard and driven by idiots, since it trundles into the line of fire and then sits there, taking damage before flying to pieces in less than a minute. It's punishing and frustrating rather than challenging, and especially annoying since there's no way to change difficulty once the campaign has started.

Of course, that same tank is virtually indestructible in multiplayer. It's here that Section 8 really comes into its own, offering an online experience that is broad in options, narrow in focus and balanced to perfection.