This game excels in two ways: one, it has a solid puzzle concept which is extended in several ways as you move through the campaign. Tools like chaff grenades and additional challenges such as noise bombs, biological tickers and oxidation packages help the game stay fresh and challenging, sure. But the true joy of the level design is the developer's ability to tweak only the most basic of rules to make sweat form on the brow of jaded veterans.

The second strong point of this game is atmosphere. Psychedelic visuals, ominous sound effects and kickass guitar riffs elevate the gameplay beyond its mere technical roots. There's nothing quite like struggling to find those last few pistons while warning klaxons blare in your ears — even people who usually associate puzzlers with sedate or boring gameplay can sit up and take notice.

There's only one major drawback, and that's the learning curve. The concept, as mentioned already, is rather difficult to grasp: although the tutorial does its best to ease players into the experience, the fact remains that you'll probably have to play through a few levels before you truly understand — and appreciate — what good fun it is. This is a very real danger in an environment where players may only give a game a cursory glance before moving on to the next title in the list, especially since the controls for the Xbox aren't quite as graceful as the keyboard/mouse combo that veterans are used to on the PC.

So what's your bang for buck?

For 400 MSP, ShellBlast HD is a pretty reasonable deal and deserves to stand out as one of the better XBIG titles out there. In addition to a 50-level-strong campaign mode, there's a bunch of replayable arcade modes such as Shell Drop which soak up further hours and make the game great for either extended sessions or quick, casual fun.

There's also a level editor and several extreme puzzles available for experienced users, extending the game life even further for those who want to challenge themselves or their friends.

If you have some spare Microsoft Points lying around, you should consider spending them on this. In an arena which is still a bit overwhelmed by sub-standard products and poorly-moderated entries, ShellBlast is a fairly good example of what an Xbox indie game can actually be. It would be quite a shame indeed if this one got lost in the deluge of rumble massagers and screensaver apps.

Additional info on ShellBlast can be found at Vertigo Games and Optum, and a more in-depth review of what I think makes the original ShellBlast awesome is hiding over here.