This game has sucked me in like an evil temptress who aims to drain the life out of me. Sorry if this 'review' ends up sounding like an ad, but that's just how good it is.
It's like a cross between the original Space Invaders and a modern Japanese vertical scrolling shooter; in fact the early parts of the game are spent watching the gameplay evolve from the former to the latter. It's available on iOS, XBLA and PSN. I paid only a few dollars for it on my iPod Touch but would have probably handed over $30 if I'd known how much fun I'd have with it.
The game's main campaign lasts for eighteen levels, starting off short and sweet and ending in a series of epic boss battles. I thought that was it, and that all that was left was to play the same levels again on medium and hard difficulty, but no - another thirty levels are unlockable, as well as several that can be bought as downloadable content, forming a second nonlinear campaign. The game can also generate new levels based on music tracks in your library, which can then be rated online. For a low-priced downloadable game, this thing is huge and full of variety, and has a ton of replay value.
The main mechanic for racking up points is keeping your 'chain level' up; that is, killing enemies or their bullets continuously in order to multiply points you earn. Stop blowing up bad guys for about three seconds and your multiplier resets. This adds a lot of strategy to the game when combined with the 7+ different weapons you have to choose from - you learn little tricks to stop the chain from resetting and have to place a lot of shots strategically. Hitting everything as quickly as possible is not the answer! Of course this has to be done while dodging a sea of projectiles and enemies that come in classic preprogrammed waves.
The graphics are incredibly simple; an updated version of the classic monochrome Space Invaders style with some background colours and simple vector graphics thrown in. Sometimes the lack of colour can make it difficult to differentiate important things from each other, but learning to do so was part of the fun for me. At times I lose visual track of where my ship is and just have to keep playing on instinct; somehow it usually seems to work out okay.
The soundtrack is rockin'. Good with headphones. Goes well with the 8-bit-style sound effects.
If it isn't clear by now, I recommend this game to anyone who owns a system for which it is available. I've only played the iOS version but it looks pretty similar on the consoles from what I've seen.
FWIW, according to GameCenter I have the 21st highest overall score at this point since that leaderboard went live - just over 18 million, on a run from levels 1-1 to 3-3 using the Gravity weapon on hard mode. Gravity is the best weapon. I'm just saying. Yeah. Maybe I've been playing this too much.
