TYRIAN. Go get it. Lite here: http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=319557685&mt=8
Give Skysmash 1918 a look, its an absolutely gorgeous world war 1 themed shmup (and you cant get much more oldskool than that!) Only 99c too
iFighter, Sky Force reloaded and Sky Smash 1918 are the best. Tyrian has dated graphics but more content than you can poke a stick at.
I'm the developer of iGuardian, maybe you can give this a try ?: More screenshots and info on: iphone-games.be or (appstore link) iTunes Store
Hey that looks pretty cool! Welcome to TA. Are the controls touch or do you move around with accelerometer? Edit: never mind, I just read the description. Has both. Looks like you released it 2 weeks ago but I don't see any iTunes reviews. You should make a thread about your game so people can see what it's about.