So here's the thing. Imagine you're the development studio behind one of the biggest gaming franchises of all time. You've had hit after hit, praise heaped upon praise and you've created games so good that people have gone out and bought consoles just to play the beggars.
Now here comes Mr Sony with his shiny new handheld, and it's your task to take everything that makes the GTA series so popular - the huge mission choice, the free-roaming, the sheer vast expanse of game environment - and shrink it all down onto a tiny little disc.
So perhaps you take the sensible decision to cut a few corners. Change to a top-down perspective maybe, get rid of the radio stations, or how about leaving out those bonus missions?
Nah. Not if you're Rockstar. Instead, you keep all those things in. Yes, all of them. And then, just to remind the world quite how good you are at this sort of thing, you throw in something extra - something that's been dreamed of, longed for and endlessly speculated about by GTA fans.
That's right, it's official - Grand Theft Auto: Liberty City Stories features wireless multiplayer for up to six players. Now, we've only played one of the multiplayer modes so far - Liberty City Survivor, which is basically deathmatch. But we can tell you this: even if the other six modes are only half as much fun, GTA fans are going to be in heaven.
The kind of heaven where instead of cherubim and seraphim you find hookers and gangsters, and where you can blow your best mates up with a rocket launcher, and where you can climb into a giant truck and run three of them over at once. Beautiful.
Setting the Tone
But first, let's take a look at the single player game - which we've also finally had the chance to get our hands on. As you'll know if you read our earlier preview, you play as Tony Cipriani, who you may recognise as the proprietor of St. Mark's Bistro in Grand Theft Auto III.
Liberty City Stories is set three years before the events of that game, when Cipriani is coming home after four years in exile. He went away after killing a made man at the request of his boss, Don Salvatore Leone, and how the dust has settled he's back in Liberty City and trying to work his way up through the ranks of the mob.
Rockstar tells us that you'll meet characters from various different GTA titles over the course of the game, as well as brand new ones. We're also told that Liberty City Stories "Ties various things from previous GTA games together," rather cryptically.
They start us off with one of the basic tutorial missions, designed principally for newcomers to the series since if you've played any of the other games it'll all come naturally. Square to jump, circle to fire, triangle to get in and out of vehicles and hold down X to sprint, at least until your stamina runs out. You can hold down the left shoulder button and use the D-pad to rotate the camera, which is designed to make up for an absence of a right analog stick.
As for the targeting system, it's based on the one used in previous GTA games, but Rockstar says a few improvements have been made to ensure it works well on PSP. You use the right shoulder button to lock on and the D-pad to cycle through the targets - cleverly, the target won't just switch to the next person along but to the next enemy along, so you won't have to keep pressing the button to ignore the innocents and get to the bad guys.
If you don't want to use the targeting system at all there's always the option to switch to free aim, and you can hold down the left shoulder button for precise shots. It's possible to customise the controls, too - you can invert them, and if the PSP's analog nubbin is proving a little fiddly for your big fat thumb you can select D-pad control instead.
Once we'd learned how to handle our weapons, it was time to get on the road in a mission titled Driving Mr. Leone. The Don asks you to give him down to the ferry port so he can catch a boat over to Staunton Island, only the cops aren't too happy about the idea of him leaving town and give chase.
And so we're off, cruising through the Portland streets in a Sentinel - just one of the vehicles to make a return from previous games. There are plenty of new ones to discover too, however, and motorbikes make an appearance in Liberty City for the first time here.
The radio stations are basically the same as those in GTA III with a few new additions, including a world music station for all you bongo fans. One new twist is that vehicles are now affected by weather conditions, so it's harder to control your car on rain-soaked streets and so on.
The Sentinel handles well and it all moves at a healthy speed, though we have to keep reminding ourselves that we're not playing Burnout Legends - for once - and can't just go smashing everyone up against the wall.
Perhaps because of this, it's not long before our car is looking rather crumpled and unwell and it's time to pop into the local Pay n Spray for a retouch. Which leaves it all nice and shiny - shinier, in fact, than you might be used to for a GTA vehicle.
"The designers actually stepped things up from GTA III graphically," Rockstar tells us. "It's the little things like reflections and draw distances, lots of small differences which all combine to make a huge difference to the whole gameplay experience."
Finally, we make it to the port. Time now for Caught in the Act, a mission which sees US behind a mounted automatic rifle on a boat that's speeding down the river. Some secret service agents are firing at us from the shore while others give chase in speedboats, leaving us blasting away wildly in all directions.
Often the agents appear as tiny specks, and getting a precise aim is no mean feat when you're on a moving boat, especially one that has a tendency to crash over piers and go soaring into the air every now and then. It's not an easy mission, and in all honesty we were completely rubbish at it. But it was fun. And we could've completed it if we'd had just one more go, honest.
We didn't get the chance to try out any of the side missions in Liberty City Stories, but Rockstar promises there are plenty to discover - and plenty of city to explore.
"We're not seeing this game as a cut-down version of any of the other GTAs for the PSP, but the next GTA in the series," Rockstar says.
"Just to put the size in perspective, if you think back to when GTA III came out on the PS2, it was a massive game to fit on the disc. We've got equal geographic size on the UMD for Liberty City Stories, and it's full 3D." Gosh.
We're impressed by the single player game, no doubt about it. The size of the playing area, the variation in missions and the intuitive control system tick all the right boxes. Not to mention the way everything looks so bright and crisp on the PSP's screen, which we're still very much in love with. But now it's time for Rockstar to show us what we've really come here to see: Grand Theft Auto multiplayer.
Let's start with the stats: up to six players can join in a wireless multiplayer game, either as teams or with every man fighting for himself. Or lady for herself - there are nine characters to choose from initially, including mobsters, hookers and a friendly-looking old lady. Who's not so friendly-looking when she's got a giant rocket launcher pointed straight in your abdomen.
As you progress through the game you can unlock more characters - there are over 60 in all, and you can earn new outfits for them too, but they all have the same abilities. To start off with you can only play in Portland Island - the whole island mind, not just a cordoned off part of it - but again, more areas are unlocked as you make your way through the game.
There are seven multiplayer modes, only three of which have been revealed so far. Get Stretch is a variation on capture the flag, where the flag in question is actually a stretch limo. Your team's mission is to nick your opponents' limo and bring it back to base, without letting them get yours out of the garage.
Then there's Protection Racket, another team game where each player is assigned to a gang and tasked with either defending or attacking a base - in a race against the clock. Once the attackers have managed to destroy four limos inside the defender's base, the timer stops and the teams switch roles. Then the new attackers have to take down four of their opponents' limos in less time than it took them to do the same.
And finally there's Liberty City Survivor, the deathmatch mode that saw us facing off with four of Rockstar's finest. We choose our character - the old lady, has to be - and find ourselves armed, dangerous and ready to kick off in the heart of Portland Island.
A map in the bottom left hand corner shows the position of each of our opponents, along with coloured icons indicating the position of various power-ups and collectables. Green means a shotgun or armour (ideally this should be your first pickup, as we quickly discovered), pink stands for a sniper rifle or rocket launcher, orange represents an AK-47 and so on.
Then there are the power-ups, represented on the map by a red star. These include invisibility - which means you won't show up on your opponents' radars, although you're still visible in-game - and mega-damage, which makes your weapon four times more powerful. Our particular favourite is Frenzy, which gives you a rocket launcher and unlimited ammo. For a limited time only of course, but for enough time to do some seriously satisfying damage.
Pleasingly, there are plenty of these coloured icons dotted around the map, so while weapons don't tend to come with a great deal of ammo you're rarely unarmed for long.
If you do find yourself in a tight spot you can always jump into a vehicle and start running people over - it won't kill them outright, but it'll take a decent chunk out of their health bar. We gave it a try and enjoyed ourselves enormously, until we realised that our more seasoned opponents considered this to be rather unsportsmanlike and ultimately an act of sheer cowardice. So we got out and said sorry. With our AK.
Vehicles are obviously good for travelling longer distances if you're after a particular power-up or a far away enemy, but getting around on foot isn't a problem. As in the single player game you press X to sprint, but now there's no stamina meter so your character won't ever get tired. It's a neat touch that reminds us this is no gimmicky add-on - Rockstar has given careful consideration to those little things which can make or break multiplayer modes.
Lock and load
After a few frantic bouts of multiplayer - during which we scored a few kills but no spectacular victories, unfortunately - it was time to go home. But first we had just a couple more questions for Rockstar regarding those things we been able to judge from our playable demo... Like loading times, for example.
"Well, the initial load will be about 20 seconds, and then loading times when you're moving from one city or island to the next will be about 12-14 seconds," says Rockstar.
"But while you're cruising around each separate borough, there are no load times at all."
And as for battery life? "A new battery, fully charged, lasts for four hours," Rockstar informs us. An impressive claim, let's hope they're right...
As you'll have realised by now, we're impressed by what we've seen of GTA: Liberty City Stories so far - particularly the wireless multiplayer feature. Cynics might question whether there's enough new stuff in here, and whether or not Rockstar has done a good enough job of getting rid of the problems which plagued San Andreas - well, not so much as plagued it, we'd say, as gave it a very mild cold.
But for one thing, we reckon we won't be able to make that kind of judgement until we've had the chance to sit down and give the game a proper going over. And what we have seen so far suggests to us that Rockstar might just have pulled it off and managed to fit yet another vast, varied and hugely satisfying game onto that tiny little disc.
Let's give the last word to Rockstar: "We know that there's a huge GTA fan base, and we know that to fail to deliver on PSP would really be shooting ourselves in the foot.
"So we were always very serious about coming up with something that meets people's expectations. And in fact, we really wanted to exceed people's expectations."
We can't wait to find out if they managed it. Roll on October 28...