There have been some great double acts in history. Sherlock Holmes had his trusty friend and sidekick, Dr Watson. Dangermouse, the heroic rodent of cartoon fame, could always rely on his old pal Penfold to either get in the way or save the day. Batman had Robin, Scooby-Doo had Scrappy, and Cannon had Ball. Maybe the last few examples aren't the best; sometimes, it seems, the sidekicks can be more annoying than indispensable. This is most definitely not the case in the weird and wonderful world of Ratchet & Clank though - the long-eared alien Ratchet and his robotic buddy Clank go together like bananas and custard.

Secret Agent Clank, however, is the first game in the series that focuses mainly on the robotic one, the ever-so cute and amusing Clank. He's been given a tuxedo (it's been painted on, by the looks of it), and a mission - he has to follow a stolen gem as it travels around, trying to retrieve it, while at the same time restoring the public's faith in his Lombax buddy Ratchet's good name. You see, it turns out that when the gem was stolen the furry one was caught red-handed at the scene. Not the sort of behaviour one would expect from such a famous hero, and the starting point (and driving force) for the whole game.

Of course, like the previous games in the franchise, you don't spend all your time playing as one character. There are long sections that see you controlling Ratchet as he fights his way out of his prison environment and, shorter, but pretty fun, sections where you control Captain Qwark (an egotistical wannabe hero who's great at messing things up and then stealing credit when our dynamic duo save the day). Fans of the series will relish the prospect of more of what they're used to; the Ratchet & Clank games have always been a subtle blend of minor puzzles, quirky humour, and... oh, what was that other thing? That's right - enormous, hilarious, ridiculously powerful weaponry. The previous games have mostly involved running around at a rate of knots, attacking everything in sight with panache and power.

This is the second Ratchet & Clank game on the PSP. The first, Size Matters, was met with critical acclaim, notching up decent scores with many publications and websites, including our own. It was, and is, a great little game, packed with firepower-filled fun; just what fans of the franchise wanted. Of course, it had its flaws, but this new title in the series has the opportunity to correct them - right? If the developers have sorted out the problems (or, at the very least, not made them any worse), then Secret Agent Clank is bound to be a good-un. More of the same, maybe, or at least minor twists on a well-tested formula.

Unfortunately, however, this hasn't turned out to be the case. If Size Matters was the perfect blend of Ratchet's custardy action and Clank's banana-ey puzzles, Secret Agent Clank is more like a lumpy mix of chocolate and sprouts. Not everybody likes sprouts, and, even if you do, you probably wouldn't fancy them with chocolate.

Clank's missions are primarily stealth-based affairs, which see you sneaking around behind your enemies' backs and waiting for gaps in their patrol paths. At times you'll disguise yourself (the very first mission, in fact, sees you hiding on various plinths in a museum as the security guards amble past, oblivious to your presence). Occasionally you get to sneak up behind an enemy who's standing still and take him down with a stealth attack. Sounds like fun, right? Well, sort of. It's not bad, but there's always a sense at the back of your mind that this, somehow, isn't what a Ratchet & Clank game should be. Why, you'll ask, are we sneaking around quietly when we could be beating the ears off our enemies?

Let's give it a chance though and ignore this series-shattering slowdown of gameplay. Perhaps the new stealthy Clank will be just as fun as the weapon-mad Ratchet of old, just in a different way. The thing is, it's hard to find out when the camera seems determined to show you everything except the areas you want and need to see. Size Matters was flawed largely because of its slightly broken camera and the programmers have obviously taken an old (but slightly distorted) adage to heart with this follow-on title - "if it is broke, don't fix it". If anything, the camera in Secret Agent Clank is worse than Size Matters. If you're trying to skirt around the vision of an enemy then it's kind of difficult when you're looking the wrong way to start with.

It's not just the camera, though, as the stealth doesn't really work very well. The enemies have almost entirely predictable (although sometimes overlapping) paths and it's impossible to avoid the impression that they exist and move purely so you can sneak around them or attack them from behind. Okay, so the enemies in every game exist only so you can destroy or avoid them, but in Secret Agent Clank the falsity is too evident, somehow. It's a real shame; if they were a little more random in their movements or if they spawned in different places when you retry a section (because you've died, again) or even if they attacked in a pattern rather than just running straight at you when they do spot you; if they could just be a little tiny bit more realistic then the whole experience would be a lot better.

You might think that the more action-oriented sections would be better, but you'd be wrong. The camera once again acts in its own strange way (maybe it doesn't like looking at the violence, or something), and to be honest the Ratchet levels aren't that much fun in the first place. They mainly consist of numerous waves of increasingly tough enemies running at you as you try your best to kill them while not throwing the PSP across the room in annoyance at the camera. The level of fun is lower, unfortunately, than the level of frustration - particularly when you die right near the end of a long series of enemies and have to repeat the whole section again. If I hadn't needed to persevere because of this review then I would have probably have given up on one of the Ratchet sections - possibly even the first one. The whole experience was marred by these frustrating and repetitive sections, which, really, should have been the most fun bits of the whole game - certainly the closest to the Ratchet & Clank formula.

Don't get me wrong; bits of the game are good. The stealth sections are, at times, fun. If you manage to get the camera right, and the timing, there is a certain satisfaction to successfully sneaking past your foes. Some of the weapons are exciting, particularly as the game progresses and, again, if you get lucky with the camera (and the positions of your enemies) then it's possible for a smile to edge its way onto your otherwise frowning features. The graphics are superb, better than Size Matters (which was no ugly duckling). They move smoothly, they're colourful and detailed, and they look different in every location. Animations are convincing and at times amusing, and everything is polished so much it shines. The sound effects and music are both great - perhaps not quite as perfect as the graphics, but very, very good nonetheless. It sounds better, of course, through headphones, but even if you're listening through the PSP's little speakers the music is catchy and the sound effects are appropriate and convincing. The little things that help draw you in are all there; the swelling music as the action rises, the mumbles and grumbles of the unaware enemies, the sirens and klaxons when you are spotted. Some of the dialogue is great too and the voice acting (and writing) is all good. On top of all this, the game will last you around ten to fifteen hours, which isn't bad for a handheld title. There's no online mode, which is a shame, but it's hard to see how one could have implemented.

However, it's not all chocolatey goodness - there are a fair few sprouts in there, many of them cooked to sogginess (I'm not really sure how I got started on this food analogy - I think it must be because I'm on a diet.) As I've already mentioned, the stealth sections don't really work. I didn't talk about the stealth attacks, other than to say that they exist, but I ought to mention how disappointing they are - you simply walk up behind an enemy (you don't even have to sneak), and then tap the square button. Then you get a couple of seconds to follow a sequence of button presses on the screen. If you get it right then you're rewarded with a pre-rendered attack scene and a dead enemy. If you get it wrong then it's the same deal, except that the enemy is very much alive at the end. Clank does have his new fighting moves (Clank-fu), which you can unlock by purchasing them from the vendors dotted around, so the fighting might have been fun. But it isn't - it's just button mashing and trying not to die.

Despite all that I've said (and it feels like I'm really slating this game), I'm still going to give Secret Agent Clank a reasonable score. You are probably wondering why and I can't blame you. It's simple - the good parts are really very good, and worthy of a decent score. In fact, they are probably worth more. Unfortunately, though, the broken bits really are broken - both in terms of this game and the series as a whole. Someone needs to let the developers know that they've got it wrong - they really need to stick to the age-old adage as it should be: "if it ain't broke, don't fix it".

Reviewed by Dom Turner for AceGamez (All Rights Reserved).