Shmup classic R-Type was released on Android yesterday, and you can grab it for 2.99 euro or $4.12 on the Android Market. For that price you get a mobile port with 3 control options to fit your playstyle, as well as a free trailer with music that doesn't sound like the R-Type I played 10+ years ago. (Then again it was 10+ years ago.)
You're probably best off taking a look at the user reviews to see if it crashes or if plays well on your Android device though. Some people seem less than charmed with the on-screen controls while touch controls seem to work better -- unless your specific Android device messes up the speed.