Let me tell you, I've had a real ball-ache of a day. I woke up this morning with a killer headache, with no idea where I was. This pretty nurse tells me that I've just had brain surgery, but that I can't rest up because they need the space for someone else - that's the NHS for you! Anyway, these two guys in riot gear dragged me back to my room where my crazy-ass cellmate was babbling a load of scary gibberish.

Things got worse from there. I found a postcard that I apparently sent to myself (never a good sign when I do this), warning me that I had to escape. Then everything went a bit mental, and someone redecorated the hospital with this unsightly peeled-bodies-and-rusty-chain motif. All day I've been hounded by these freaky guys with mouths in their chests, and by these ugly worm things that squeal like babies. Thank God I keep finding painkillers all over the place; I must have chowed down eight bottles, and now I'm tripping my tits off...

Oh well, at least I have Dementium 2 to cheer me up. Unlike their film-based equivalents, video game sequels tend to be an improvement on their predecessors - and the new game from Renegade Kid is no exception. Indeed, that's a massive understatement: the Texas-based developer has taken everything that was good about the first game and made it even better, resolving the few flaws that were present and then throwing in a whole load of new tricks. And on the basis of the two chapters I've played so far, I'd say this could easily be one of the best DS games I've played all year.

Like the first game, Dementium 2 is a FPS survival horror that finds you battling demonic abominations inside a run-down hospital. The player takes the role of William Redmoor, a damaged and possibly schizophrenic hero who's just "had some work done" at Bright Dawn Treatment Center. It was eventually revealed that the whole of the last game took place inside William's head, but it soon transpires that real life is just as nightmarish, if not worse. Are you crazy, or is there a good reason why everything has gone all Silent Hill? We just don't know yet, but to find the truth you'll need to fight your way through a new set of freaky-looking nasties.

In broad terms, Dementium plays in exactly the same way as the last game - kill lots of monsters, search every room for health and ammo, and occasionally solve a puzzle to access the next area. It's a classic survival horror template, but the big draw here is quality. My last preview covered a lot of the changes to things like the inventory and save systems, but with hindsight I didn't make a big enough deal of how great this game looks and sounds. If you want an easy point of comparison, you need only look at the Chest Maws - the zombie-like creatures with vertical jaws on their torso. Last time around they were merely an odd-looking threat; this time they're genuinely nasty. When they open their massive gobs you can see a rotting heart lurking inside the chest cavity, and when they stumble towards you they move with a creepy, juddering motion.

These flesh ball things make drilling noises as they attack

A similar degree of detail has been applied to your surroundings. In the last game things got quite samey, but this time there's plenty of variety between each area. As a result, Bright Dawn Centre actually feels like a proper mental hospital (or a proper dilapidated mental hospital, at any rate). As it turns out, Bright Dawn is only one of many environments you'll encounter. The first chapter wastes little time in dishing out cool stuff, serving up your first boss and three separate weapons within the first half hour of play, but it's doesn't take long before you escape to the outside world. At the start of Chapter 2 you'll find yourself standing outside in the snow, with white flakes tumbling down all around you. It's a startlingly pretty moment, particularly if you're well versed in the claustrophobic maps of the last game. Still, it's not quite as startling as what you'll find yourself doing about half an hour later, shortly after picking up a spade (i'm not telling you; you'll have to see it for yourself).

As nice as the new graphics are (and they really do look great), I'm even more impressed by Renegade's work on the audio front. The first Dementium gained a lot from its clever use of sound, but I was still taken aback by the spread of brilliant noises in this sequel. From the barked threats of Bright Dawn's guards to the sinister mutterings of a Russian prisoner, everything has a role to play in contributing to the game's atmosphere. Many of these effects work well with particular gameplay aspects. Since you have to manually reload your revolver by tapping a button on screen, it's quite easy to empty all six chambers; should this happen you'll hear a panic-inducing click. And since each of your enemies makes a distinct noise, you'll often know what's waiting for you around the corner... unless, of course, you're hearing something entirely new - in which case you'll probably lay a brown egg in your pants.

While we're on the subject of enemies, it's clear that you'll be facing a far wider selection of monsters during this second outing. Along with the Chest Maws, you'll be pleased to know that two old friends have made a comeback: the flying skulls and baby-voiced worms have both returned to the fray. Other creatures you'll meet include a four-legged monster with two faces that laughs hysterically and spits at you, and a winged ball of flesh that makes a drilling noise as it dives into you. There's also a mad doctor who appears to be your ultimate nemesis, taunting you over Bright Dawn's PA system in the manner of BioShock's Andrew Ryan.

So yes, Dementium 2 looks and sounds great - but it also has a habit of surprising you. There's a great example of this early on in the game, where Renegade Kid abruptly changes the rules to take the player out of their comfort zone. You've just found the sledgehammer, a meaty weapon that floors most foes, and as a result you may be feeling quite confident. Then, all of a sudden, you meet an enemy that can't be killed - a smoky black ghost that whispers your name over and over as it slowly drifts towards you. If it catches you it'll teleport you to an arena filled with enemies, and so your only hope is to run away through a maze of sewers. You'll have to find your way through a brand new area, jumping over pipes that block your path and making blind guesses when you reach a fork... and all the while the whispering phantoms will be at your back.

In case you can't tell, I'm rather impressed with Dementium 2. This is Renegade Kid's third entry into the FPS genre, and it now feels like the team is hitting its stride. There's no confirmed release date yet, but we'll certainly let you know when we get one; if you own a DS, this is definitely a game that should be on your radar.

Dementium 2 will be released exclusively on DS at a future date TBC.