Sony Online, famed for its success with EverQuest, is working to complete another massively multiplayer online game in time for this summer. However, unlike most other persistent-world games, PlanetSide is a first-person shooter with a futuristic, sci-fi theme. At first glance, the game looks very much like a massively multiplayer version of Tribes, with similarities in the form of bases, large maps, and drivable vehicles. Closer inspection reveals that there's a lot more depth involved in PlanetSide, with its elaborate skill system, much larger bases, maps that seem to extend for dozens of miles in every direction, and a lot more choices in vehicles and weapons. That level of depth is to be expected, as the challenge for PlanetSide's designers is to convince multiplayer action fans that there's enough that's unique about the game to justify paying a monthly fee to play it. After getting a chance to play the online press beta, we're intrigued with PlanetSide's potential.

Antivehicle specialists can also take out turrets with their weapons.

PlanetSide features three playable factions: the Terran Empire, the Vanu Sovereignty, and the New Conglomerate, each with its own style of weapons and technology. The world is divided into several large continents, each of which has about a dozen or more bases scattered around them. PlanetSide's gameplay centers around the three factions' struggle to control the bases and hold territories from enemy attacks.

Bases are massive in size, dwarfing the largest ones in Tribes 2. Even with a few hours of gameplay under our belts, we still found ourselves getting lost inside some of them. A base filled with defenders who are manning gun turrets, creating vehicles out of the vehicle station, and guarding the vast interior architecture is extremely difficult to take over. It's pretty safe to say that lone wolf players or even a small band of three or four would have very little chance of capturing a well-defended enemy base. Raids require a concerted effort from many players with different skill specialties.

When you first start in PlanetSide, you'll appear at your faction's home sanctuary, which is a safe haven where weapons cannot be fired and you can take a breather. The sanctuary is the place where you can recall or warp yourself, should you find yourself lost out in the middle of nowhere, without a vehicle to get back to a friendly base. At the sanctuary, you'll find various stations to outfit your character, including equipment stations to pick up weapons and items, as well as certification and implant stations.

There are several continents to fight on, with varying terrain.

The certifications in PlanetSide are the central way in which you specialize your character and earn the right to use certain weapons and items and to drive vehicles. Unlike Battlefield 1942, where you can pick up and use any weapon off the ground or hop into any open vehicle, PlanetSide requires that you first gain certain certifications to use those weapons or vehicles. Basic certifications in areas such as assault, hacking, repair, vehicle use, and armor use are available. Once you're certified in the basic categories, more specialized options are available.

For example, you can pick sniper certification under the weapons category, which opens up the sniper rifle for purchase in the equipment station. Heavy-weapons fans can pick up heavy-weapons certification and a "max" suit, which has the most inventory capacity and damage absorption. Or you could choose repair skills and certification for several vehicle types to become a pilot and engineer. Another popular set is the cloaked infiltration suit (it bends light around it like the Predator's, making you practically invisible while stationary) and hacking skills, a combination that allows you to slip almost unnoticed into bases and hack the control point. There's a wealth of possibilities for you to create your own classes, depending on how you spend your certification points.