To adequately recreate the experience of playing Gungrave: Overdose, jam on the Square button for about an hour and a half, occasionally switching up to press Triangle, Circle, L1, or R1. The PS2 doesn't even have to be on. Just pretend that what's going on onscreen is really cool and you've got it down.
Gungrave: Overdose is essentially the same game as its predecessor, the underwhelming but briefly entertaining Gungrave, but there's a bit more to it. It's more anime-styled mayhem starring a dead guy, his enormous and perhaps physically impossible handguns, and like five thousand dead gangsters, but it lacks some of the "lean on Square long enough and you win" feel of the original.
Three years after the destruction of the city of Billion, Mika is forced to reawaken Beyond the Grave (just "Grave" if yer nasty). The Syndicate may be dead, but the danger posed by the drug known as Seed isn't.
To hunt down the remaining dealers, Grave's been given a new coffin, some new moves, the same guns, and essentially the same graphics. In addition to charging up your devastating screen-clearing Demolition Shot, you've been given an upgraded coffin.
Grave used to swing his coffin as a short-ranged melee attack. It now also serves as a shield, allowing you to block, and you can swing the coffin to bounce incoming missiles back at the guy who fired them.
You can also hold down Square to charge up Grave's pistols. Once charged, you can release Square for up to four powered shots, each one of which automatically locks onto viable targets within Grave's line of sight.
Once you clear the first stage, you unlock two new characters: the undead samurai Juji Kubane, who is to melee attacks as Grave is to guns, and Rockabilly Redcadillac, a ghost haunting an electric guitar whose name causes me almost physical pain.
As any of these three characters, the name of the game is violence. You'll be sent into several environments teeming with gun-wielding mobsters, where you are to shoot, stab, bludgeon, or explode them all. Sometimes there will be many of them; sometimes there will be fewer of them but they'll have gadgets like rocket launchers. A few have swords which sometimes deflect your bullets, and every so often they'll be taking cover behind something that'll explode when shot.
You don't really play Gungrave: Overdose. It's like a sort of Zen meditation on gunplay and the style thereof. All the little touches from the last game are back, like characters starting to pose if you stand still while firing, the Halo-esque shield gimmick, or the totally ineffectual shootdodges.
In between stages, you'll be treated to some really good-looking anime-style cutscenes, which blends hand-drawn art with cel-shading to create a wholly unique look. The cutscenes, sadly, may be the best part of the game, or at least the part of the game that best captures the look and feel of the show.
The rest of the time, you'll be blazing away at a never-ending supply of faceless goons, with an occasional timeout for a boss fight against some over-the-top weirdo in a death machine. As an example, the first boss softens you up with an attack helicopter, then comes after you in a cybernetic desk chair and finally tries to take you out with twin pistols.
If Gungrave: Overdose tried for the same kind of relentless variety and imagination that other decent shooters do, it'd be a worthwhile game. A bit of that old-school Konami sadism, such as that found in Contra, would be welcome here, but instead, it's really just shooting guys a lot. The extra characters and moves let you change up the manner in which those guys are shot, and the extra types of enemies force you to shoot them in a slightly different way, but you're still just mowing down another horde of ruthless yet stupid gangsters.
For fans of the show, Overdose will provide you with a bit of the same too-cool-for-its-own-good feel, but it lacks the quiet film noir moments of the best episodes. The focus is entirely on gunplay here, and since Grave never earns any new moves worth speaking of (as in the first game, you can gradually unlock new kinds of Demolition Shots, but your basic moveslist will stay the same for the duration), it's particularly boring gunplay.
It's worth mentioning, in closing, that Overdose is shipping to stores with a suggested retail price of $14.99 and a free trial subscription to play magazine inside each game's case. While that is indeed ridiculously cheap, especially for a brand-new game, you're really paying for carpal tunnel. There are better button-mashers, better shooters, and better games based on anime licenses out there.