Android : https://play.google.com/store/apps/details?id=com.TreSSor.DeepSpaceInvaders
iOS : https://itunes.apple.com/us/app/deep-space-invaders/id941207420?mt=8
Deep Space Invaders is a FREE Shoot'Em up style game for mobile Android / iOS , Destroy hordes of enemies and collect power-ups and buy enhancements to upgrade your spaceship . The difficulty increases over time .
