Just finished the the tutorial and first level. The game is, without a doubt, beautiful. The combination of detailed sprites and 3D objects is seamless, framerate is very high on my 3Gs, and the animation is fluid. Visually, this is the most stunning shmup I've played on the platform. The controls are responsive and well designed, particularly considering the variety of gameplay involved. Hey, they even have manual shooting option, something that's rare for this genre (in the App Store, anyway). The first boss was massive and fun to fight.
That said, the combination of physics, shooting, and swinging action is a bit strange, and I'm still not sure what I think of it. Focusing on breaking through an obstacle at the same time as you're shooting hordes of enemies is difficult; I wonder if it will get frustrating as I make my way through the game. At this point I don't feel that I have quite mastered the Eveningstar swinging motion (that's the glowing ball around the ship in the video), though it did get easier the second time I went through the level (the boss killed me the first time).
My other concern is length. That first level was pretty short (though challenging at medium difficulty); if the other 8 levels are the same length, the game will be over in no time. Perhaps the developer can chime in about this, as well as plans for updating with new content (if any).
Eveningstar is definitely a unique take on the schmups genre and I'm glad I've picked it up. But I think the developer would be wise to release a lite version in the future, just to give folks a taste of the gameplay before purchase. In the meantime, people may want to hear further impressions before they jump on board.