Games: When worlds collide

Conquer-crazy aliens aren't anything new. Since "Space Invaders," evil extraterrestrials have sought Earth's end at least twice a week within gamers' collective homes, and "Universe at War: Earth Assault" is no exception -- a basic, but enjoyable strategy game that finds Earth as the flash point for three alien armies.

With our tender terrain turf raked by all matter of death rays, will a grizzly gang of survivors hold the line for mankind? Nope. Technologically outranked, human forces fold to the aggressive Hierarchy, galactic conquistadors that plan to mine our planet dry. Instead, you'll carry the attack in the game's campaign mode as the Novus, a noble race of robo-clones that've hunted the Hierarchy for decades. Sleeping beneath the Sahara's surface are 'Universe's' last playable species -- the Masari, a once-dormant group with a score to settle against the Hierarchy, who betrayed them eons ago.

The trio of alien factions may not be the most original -- the Masari draw from "Stargate" and Egyptian mythology; Novus are factory-bred anime lookalikes; the Hierarchy's lumbering walkers tip their hats to "War of the Worlds." It's a cobbling of major sci-fi franchises, but the visual distinctions do their job to separate the factions on screen and during combat. The Novus, for example, excel at hit-and-run tactics and rely on network nodes to zip across the map, and their specialized hackers can disable enemies. The Masari are a little more defensive-oriented and great at gathering resources, but versatile upon greater inspection -- their units' abilities change depending on whether they're in "light" or "dark" mode.

The Hierarchy are heavyweights, and their city block-sized, four-legged walkers are worth highlighting. More like mobile barracks than a battle tank, these customizable colossi pack eight hardpoints players and can plug radioactive artillery, repair chambers, turrets or extra armor into, not to mention hardware to crank out smaller soldiers and flying saucers. They grant the Hierarchy a uniquely mobile style of offense, but the walkers also make fantastic foes -- separated weapons systems mean you'll need to focus your fire on single sections to bring one down.

"Universe at War" gets points for handing gamers a hill-shaking, plasma-spitting battle factory-fortress to play with, but what else has it got? Comfortable controls. Tailoring a genre meant for mouse and keyboard for consoles isn't a simple task, but Petroglyph retains good usability by transferring commands to the triggers, which control the mini-map and bring up building options. With specialized hero units, air vehicles, teleporting androids and research trees to micromanage, the nuance shouldered by the armies isn't lost between your thumbs.

"Universe" figured out a great feel for its gameplay and controls, but the game's visuals actually manage to detract from these areas. Units are generally stylistically interesting (like the Hierarchy's gatherers, which zap up scenery like cows, cars and scrap metal for resource points), but don't sport the high-polygon models you'd find in smaller-scale games. Low-res characters are usually excusable in RTS titles, but in this case the trade-off isn't accompanied by a smooth frame rate, which stutters during major battles. "Universe" slows to a crawl anytime a couple dozen units are trading fire in front of a base, and this makes it difficult to assign instructions to troops and manage the flow of battle.

The sluggish frame rate isn't an outright game-breaker, but it's a shame Petroglyph couldn't piece together a console version that runs smoothly in all scenarios. The rest of its presentation is pretty good, especially the soundtrack, which is scored by former "Command & Conquer" composer Frank Klepacki. A handful of destructible buildings, persistent shrapnel, cratering and lush terrain flesh out the game's flora.

"Universe at War" is a solid strategy title that's stymied by a subpar graphics engine. The campaign mode is full of plain, cliched characters, but the complex, distinct playing styles of the three factions take their place. The main issue here is the middling visuals, which can't seem to keep pace with "Universe's" fun, well-designed sci-fi combat.

"Universe At War: Earth Assault"

Platforms: Xbox 360, PC

Developer: Petroglyph

Publisher: Sega

Genre: Real-time strategy

Rating: 2.5 / 4

Fun: Three distinct alien races to lead into battle; massive four-legged walkers are elegant, well-executed console controls; awesome mobile fortresses; four-person online multiplayer; savable single-player games.

Unfun: Graphics stumble when firefights get intense; uninspired story; low-res enemies; campaign's escort and retrieval missions get tedious.