Steel Battalion and its Xbox Live update, Line Of Contact, must rate among the most daring videogames of all time.

Its creator, Atsushi Inaba, was so unsure how Capcom would react that he conducted a large part of development without letting even his bosses see it. Releasing a 40-button controller that could only be used with Steel Battalion games was a big gamble for Capcom, not just because it's expensive but also because it demands some serious dedication as a gamer.

Committed is one word for the Steel Battalion online community, but obsessed is a little more accurate. Don't expect to sign in and discover hordes of badmouthing children because most SB players are in their 20s and 30s, and totally serious about making the most of their £120 investment.

They're not only addicted to the intense three-on-three mech battles, but a whole host of features that you might not expect. Online trading, auctioneering, chatrooms and lobbies tailored for tactical planning demonstrate how the game integrates Xbox Live in new and advantageous ways.

At the heart of this online revolution is Campaign mode. Campaigns last for 60 real-time days with four armies of about 1,000 players competing over 100 territories. At the end of each week, Capcom's server tallies up how many skirmishes your army has won and awards territory to the victorious force. A single victory in battle, although important, won't change the overall outcome, transforming Campaign mode into a team effort on a massively multiplayer scale.

Players who thrived on the individual achievement of MechAssault online will still find satisfaction here, though. Medals, titles and rankings are awarded to expert players, displayed on your profile for everyone else to see. Aspirations are high and everyone wants a profile that will make new players shudder with fear.

Being a novice player isn't at all fun, unless you stick to players at your own level. Optimatch helps with this, but it won't help you to learn the controller inside out. Neither will it assist you in unlocking the more powerful Vertical Tanks (VTs) that only high-ranked players can purchase. At least you can be sure of earning ranking points, whether you stand triumphant or end up as smelting material.

Having only three VTs to choose at the start does seem a little too restrictive, but that's where trading and capturing comes in. Drop into any chatroom and players will be willing to trade VTs that you can't normally use, including some that Capcom releases onto the servers as limited editions. There's also a market for second-hand equipment, saved action replays and custom insignia designs. Capturing VTs is an evil technique where you deliberately shoot an enemy's legs off in battle. Their souped-up pride and joy then becomes yours to use or even sell back to your tearful victim.

All of these unique features create an unexpected MMORPG out of a graphically stunning mech warfare game. Most of the screens on this page are from Replay mode, the best way to appreciate the dirty but strangely alluring environmental effects. The VTs are also spectacularly designed, mind-boggling when you think that there are more than 30 to choose from. In-game, you're always confined to the cockpit view, but even this is intensely detailed and different for every single VT.

No matter how compelling, Steel Battalion does still have technical faults. The learning curve is absurdly steep (a good excuse to practise with the offline prequel), the interfaces are cumbersome and the servers are often laggy and unable to cope with five-on-five battles.

However, if you're looking for a game that truly makes the most of Xbox Live features then this is the most inventive to date. Teamwork on an epic scale and a simulation so realistic that you can almost smell the napalm makes this undeniably the greatest robot-fighting game of all time, albeit one you'll have to pay a premium for.

1. Demands teamwork
2. Rewards individual achievement
3. Trading VTs is entertaining
4. Insignia tool

1. Evil learning curve...
2. And it's exhausting!

Power
Graphically photorealistic. Makes the industrial look elegant and beautiful. Lighting is mesmerising.

Style
Menus aren't user-friendly, but the cockpits and VT exteriors are elaborately detailed and look ace.

Immersion
A fantastic simulation of futuristic warfare. The 40-button controller makes you feel like you're there.

Lifespan
New maps are released every week - the server chooses which ones you play. Plenty of longevity.

Summary
The best robot game ever. MechAssault and Phantom Crash can't even compete. Good luck finding the controller, though.