I have to start by saying forget anything you've heard about this game looking like a PS2 game. I have no idea what hallucinogenic drugs these people are taking, but they are bad, bad people who hold the PS2 in much higher regard than it deserves to be held, viewed through the mist of fanboyism.
Bullet Witch made me happy. The 360 is dominated by tactical shooters like Graw, Gears of War, Rainbow Six, and to an extent Halo, so it nearly made me cry tears of nostalgic joy to be given a big gun and told, quite simply, to execute everything that moves with no regard for reason or realism.
Along the lines of Crackdown, this is not a game grounded in creating a realistic world, it just wants to be cool. It fails and succeeds alternately for its 7-ish hours of gameplay, but for the most part this game is great.
The biggest downside is that the levels are set out in an infuriating half-way point between the standard restrictive third person on-rails design and some kind of almost-GTA level of freedom. Because of this, the game gives you maybe 3 or 4 paths through a level, only one of which will actually get you anywhere. This is bad. This is so bad I nearly gave up playing on the second level.
However, I couldn't switch my 360 off. The sheer scale of the buildings fascinated me, and the first fight with a Giga (a giant, quite like the Resident Evil 4 ones, only of a much more terrifying scale, and with godawful AI, another pitfall of Bullet Witch) was great. It was impossible for me to disengage with the game, I needed to go on, driven by an unknown force... The witchcraft deserves mention for being especially over the top, graphically and gameplay wise.
Graphically, I love this game. I see partially where the PS2 comparison comes from, there's an odd squareness to all the level design that makes it feel antiquated, but the draw distance, the horizon, and the scale of everything really sucked me in. And Alicia (the witch in question) has a delightful bum.
Which is largely what this game is about. A pretty lady with a big gun jumping around and killing huge - HUGE - enemies, and engaging in the destruction of buildings willy-nilly. It's utterly brainless, though it has excellent (comparatively with most Japanese conversions) voice acting, and a semi-decent story with gorgeous cutscenes.
You should at least rent this game, if for nothing else because it's almost unique on the 360, and because this sort of thing should be encouraged.