Bugatron for Mac

From Red Marble Games:

Bugatron starts with classic retro arcade fun and then takes it into a new dimension -- literally! Bugatron is an all-3D arcade shooter that sets itself apart from all the clones with unusual level design that reinvents the genre. You don't just blast diving, swooping enemies. It starts there, but you'll also find:
Bugs that orbit, hide, dance, disappear, and whoosh out of the screen
Unique powerups that you've never seen before -- and some you need to avoid
Bonus levels that challenge your shooting skills
Cool retro music and sounds
Bright, shiny, colorful 3D graphics
The free demo comes with 16 levels; the full registered version has 88.