Mercenaries: Guns for hire head to PS2 and Xbox

So how do you get between different areas? Is it just a huge world you explore at your leisure?
We have seven separate maps. The ace of clubs, hearts, diamonds and spades are the top boss characters and we've built a custom map for each one of those. There's an intro map - we wanted to make sure that in wrapping the player up in how the game works that we built a very structured environment. And then we have two giant maps: North map and South map. That's where the bulk of the gameplay takes place. You unlock the second map after you complete the first 24 missions. But it's all one continuous load, actually, as we're streaming off the disc.

So you get between the maps by...?
Just driving [laughs].

So you can just drive between all seven maps?
Once you complete an ace mission, you'd have to load a previous game to go there again as there's no reason for a player to go back. You're going to get all your dynamically-generated missions from those two main maps.

How does the mission structure work?
The only firm framework we have is that set of 52 cards representing the 52 fugitives. You have to do them in order. So you start with the two of clubs, then you get the three of clubs, four of clubs and so on and once you get the ace of clubs you start on diamonds. So they have to be done in order but what you do in between, earning your money and playing with your faction ratings, is completely up to you. And then there's the missions created dynamically on the fly, such as 'I need you to steal X from location Y', which are different for each faction as well... I've never finished Vice City because I spent too much time running around playing in the world. And Mercenaries is similar in that it's definitely an open-ended game in the GTA genre. But the 52 missions are a nice marriage, so you do have a structure, the character always knows what they need to do next to progress but they don't have to do it - they can screw around, have fun, do whatever they want. Also, it's not just mindless action as you're earning money along the way.

How do you balance the difficulty of the game, as you go from a boss battle with the ace of clubs to the next target which is a lowly two of diamonds?
Balancing and tuning this game is giving everyone ulcers as it's so big but it is just a matter of tuning. When I worked on the Medal of Honor stuff [before moving to LucasArts], we would ramp our game in an up-and-down kind of way, not setting the difficulty in one straight progressively harder line. It would be hard, then we'd turn it back down a little, then you worked your way back up with the next peak a little higher. For example, you get the ace of clubs - who is a scientist building a chemical weapon - and the next mission is the two of diamonds. It could be a guy who is a black market arms dealer, so it's going to be a lot easier but it's in a totally different kind of context and by getting him it'll open up access to some new weapons. That kind of ramping - where it's hard and then you reset it a little bit - I think that can actually work pretty well, as it gives the player some kind of breathing room.

In our experience gamers are pretty bloodthirsty - they'd probably rather kill an enemy with a sniper rifle than tranquillise and capture them. Is that a problem?
They'll learn if they want to earn more money that's not the best way to go. But it's up to them, they can do that. In a way, it's a shopping simulator for boys: 'I want buy a tank, I want to buy a hummer'. There's a huge incentive to go after those bounties and capture the 52 fugitives because you get dramatically more money. It's very easy to call in an air strike to kill your target but on the lower cards you'll be spending more money than you'll earn from the job.

Can you run out of money? And is that game over?
You can run out of money, sure, but it's not game over. You just take a new job - there are plenty you can do that don't require cash up front. And you can always steal stuff.

What do you see as the game's unique selling points?
It's a combat experience that no one has ever seen or played before, where it's this big open environment, where everything you think you should be able to do, you can. Then there's the Havoc physics library (which is a big selling point of Half Life 2) - the fact that we've incorporated that on to a PS2, I bow down before Pandemic for pulling that off. And just look at it. The particle system for all those effects is all hard coded. The payoff for the player's actions is so intense and so deep. I think people play games because they want to have an impact on something. And the player definitely has an impact on that world [in Mercenaries] from the most extreme example of bringing down a building to the smallest example of taking UN inspectors to a weapons site - earning dollars, protecting them, finding WMDs. It just has so much depth and is such fun to play. It's a great sign for a game when the team spend a long time playing it when they're supposed to be working on it. Hours and hours have been wasted playing this game!

Mercenaries is scheduled to land with a bang on PS2 and Xbox in the autumn. A PC version is on the cards after the console versions have been completed