Sierra 7 is an interesting on-rails shooter that is marred by annoying free-to-play design.

Mighty Strike Team is an old school single screen shooter. It's familiar yet fun.

Angry Birds Stella POP! offers some fun twists on the bubble shooting formula, but it suffers from some big difficulty spikes.

More hands-on than most Tower Defense games, dooDlefense doesn't entirely succeed but it's a neat idea.

Top Tank is a simple yet quite entertaining way to blast everything in your path.

Random Heroes 3 offers up more of the good stuff (e.g. shooting and destruction).