The more time that passes in the gaming world, the more it seems people miss the days of arcades. A variety of "retro arcade style" titles have been cropping up over the past few years, with the most recent entrant the arcade 'shmup styled Vortex Attack from Kaleido Games. Fans of Galaga should inquire within.
You're familiar with the drill at this point: aliens invade/attack, we have to repel. The catch here is that in order to prevent more invaders from spawning, you have to kill them to gather their energy and use that to close the "vortices" from which they emerge. Past that, the usual routine applies: clear the stage, rack up points, rinse/repeat. You can also team up with up to 2 other local friends to really take the fight to those alien scum.
Vortex Attack is available now on Steam for just $4.49 until June 3, and then goes up to its regular price of $4.99 after that.