Comparisons between Blast Factor and Geometry Wars are unavoidable. In truth, Sony's downloadable games service launch title is more akin to PomPom's Mutant Storm Reloaded (Xbox Live Arcade) both in gameplay and price. We will say, of the three (Blast Factor, Geometry Wars, and Mutant Storm), Bizzare's $5 gem still trumps all in aesthetic and pace.
Where Blast Factor lacks style it makes up for with dynamic gameplay elements, including the most effective usage of Sixaxis's motion capabilities to date. While deceptively simple, the act of jerking the controller left or right to slosh around the liquid within each stage (corralling the enemies) typifies a clear advantage PS3 could have over Xbox 360 -- though the lack of rumble certainly damages the game's 'blast' factor. Other noteworthy devices include Blast Factor's auto-adjusting difficulty and enemy variation (players must discover how each class of baddie is defeated).
There are some quibbles that make Blast Factor's $9.99* price tag difficult to swallow. That each level (there are seven) contains an identical stage map, with each stage bordered by the same hexagon, is disappointing; that each level's boss is essentially identical is even more disappointing -- and puzzling, given that Bluepoint designed a decent range of non-boss foes. Still, we would have be willing to look past these faults if Blast Factor sustained that frantic whirlwind of action so elegantly composed in Geometry Wars. But it doesn't.
*Blast Factor is currently on sale for $7.99.