I've just picked up on Hammerfall via the ever-excellent physics-game site Fun Motion, who in turn discovered it on the Russian-language game development forums at GameDev.ru. The game's hour-long demo was posted as an example of work-in-progress - and it's looking fairly polished.
Hammerfall's concept is simple: it's a 2D weapon-swinging game. However, the weapon swinging is a little offbeat, since you're the pilot of a steam-powered clockpunk helicopter-thing, which has a weapon dangling from it on a chain. You start out with a rock, and end up with hammers and big shiny switchblades. Using these whirling weapons you have to fight off a series of enemies, swarm shoot 'em up style. Evil night maggots and airship-eating wasps, as well as other heli-weapon pilots, all mean that mastery of your martial pendulum-device is essential. It made me feel a bit weird, perhaps dizzy in two dimensions, or something.
Hmm, I don't think my screenshot quite captures the action... Anyway Hammerfall's tiny skybound fantasy universe is just beautiful and I recommend it to all. As long as you don't mind being referred to as "The Gaiar" by your weapon-whirling tutors.