Killzone: Mercenary feels like the realisation of a dream, albeit one from 2004. It feels like the long-coveted 'PS3 in your pocket' is actually here: playing the preview code reminded me just how powerful Sony's handheld is. Mercenary is, in terms of pure graphical grunt, one of the best-looking games I've ever seen on a mobile device.

Helped no doubt by that excellent screen, it's as sharp and detailed as you could hope for, with excellent volumetric effects and wonderful lighting. In terms of looks, it's as much a Killzone game as you could hope for. It's what we were always promised, way back when the PSP launched.

Things are different now, of course, and that sort of attitude doesn't cut it anymore. Killzone may be the realisation of Kuturagi's rather misguided vision of the future, but it's also a reminder that, on the whole, Nintendo is still the king.

In fairness, from what I've played - and this is preview code - it's not a bad game. Concessions have been made to the mobile format. There's a lot more in common with Call of Duty than Killzone here, and that's no bad thing. To accommodate the portable nature of the system, now everything is about loadouts, persistent challenges, unlocks, credits and upgrades.

Killing enemies nets you points, with more adventurous murder - headshots, melee, stealth, double/triple kill (you know the drill) - rewarding you with more score. You then trade these points in at your friendly neighbourhood arms dealer, encouraging better play for better kit. Your points score is then put up for all to see on the leaderboards.

And it can be fun. Killzone's industrial vibe is hardly the most inspiring style in the world, but its shooting is solid, the upgrade system is fun, and well, it simply looks brilliant. It's just that it doesn't feel - for all of the aforementioned concessions - like something that I would want to play on a handheld - highlighting the inherent flaw in the powerhouse, twin-stick philosophy that underpins a lot of what Vita is about.

Not that Killzone: Mercenary is totally indicative of what the Vita represents. Games like Tearaway are inventive pieces of software you can only really play there. But it's a damning indictment of the tech-lust attitude that still lingers around Sony's handheld offerings, of shrunk-down versions of big-screen hits, and the firm can ill-afford to continue down that road. Black Ops: Declassified was an extraordinary clunker, another example of how wanting home experiences on handheld doesn't really work out.

That Declassified was terrible didn't help, but even if it was good, like Killzone can be, would it have mattered? Probably not, because these types of experiences are better served at home. Which, coincidentally, is where a lot of handheld gaming is played. Who's going to opt for an inferior version when the real thing is just a front room away?

Compare and contrast to Nintendo, which is on a huge roll at the moment, and one that's due to continue with the likes of Pokemon X and Y, among others, heading for the console.

Nintendo has always known how to play the game on handheld, and while Killzone is impressive in some ways, it marks what should be the death of one of Sony's old dreams. Good: the PSVita is a wonderful console, that pushes new boundaries in mobile games. But it doesn't need to be saddled with old ideas. PS4 will help give the Vita new lease of life, but it can't do all the work.