The "Metal Gear" series pretty much invented a style of military action video games where sneaking around and a sly sense of humor are at least as important as blasting away.

Two new editions in the series make this clear.

"Metal Gear Solid 3: Subsistence" for the PlayStation 2 adds long-sought online multiplayer battles, while "Metal Gear Acid 2" for the PlayStation Portable keeps things fun and kitschy by including a 3D viewer.

Those who played last year's "Metal Gear Solid 3: Snake Eater" will find something oddly similar about "Subsistence." That's because it's the same game.

Well, not entirely.

The re-release of sorts — rated M, for mature — from Konami Digital Entertainment-America has been reworked with some worthwhile extras.

The single-player experience is mostly unchanged — a good thing for one of last year's best action games.

Set in the 1960s during the height of the Cold War, you play as Snake, an American superagent who must infiltrate the Soviet Union and stop a next-generation nuclear tank that could tip the scales of war in Mother Russia's favor.

The online multiplayer modes are completely new.

You can do battle with as many as seven others in the usual kill-or-be-killed death-match arena.

But I found the sneaking and rescue missions particularly fun because they require teamwork and fit perfectly into the game's stealth combat design.

One caveat: Though free as long as you have the required broadband Internet access, the system for connecting and playing online is rather clunky and prone to disconnection in my experience.

"Subsistence" also includes two previously unreleased "Metal Gear" titles from the last century for us old-school gamers: "Metal Gear" and "Metal Gear 2: Solid Snake."

"Metal Gear Acid 2" (M-rated) brings more of the same turn-based strategy to the PSP system as last year's version, with only a few new twists.

Compared with "Subsistence," it's a slower pace, where you draw from a deck of cards that determine if you can evade or attack through treacherous warehouses and other enemy bastions.

After your move, the enemies all get a turn, and in that way it's much like a chess game — but with machine guns and stun grenades.

The graphics this time around have been redone in a cell-shaded, comic-book style that looks bright and clear on the PSP's spacious screen.

An included paper and plastic accessory fits around the PSP and lets viewers watch some of the game's lengthy cut-scene movies in full 3D. But it's more of a gimmick than anything else and had me rubbing my eyes after only a few minutes.