Isotope! Also Meteor Blitz, Alive 4 Ever (1&2), Pew Pew (1 & 2), Bug Panic, Solomon's Keep, Max Adventure and Geometry Wars Touch...
I always, ALWAYS find myself coming back to Meteor Blitz after so much time. But I guess you can say that Deadlock is going to be worth the wait
Mushihimesama Bug Panic Solomon's Keep/Boneyard Honorable mentions to Max Adventure I wanted to like Bug Heroes, but the game felt too slow for me. I probably should have played it first before M. Bug Panic... M.Bug Panic is not a "traditional" dual stick shooter, but its definitely a fast & frantic game (especially multiplayer..if you can find people to play with).
Minigore, at least it's fun for a while, great one more try, but not so good for a story, I still kinda like it.
Meteor Blitz Space Miner Isotope Alive for Ever There are a lot of nice ones, but the ones above were the only ones that kept me coming back.