I bought this game on mobile recently. It’s a bit like Geometry Wars - you have a small arena that you can move around in. Instead of precisely controlling where you want to move, you tap on the screen and the ship moves there. To destroy enemies you have to get them to move directly behind you so that you can “backfire” bullets into them. It’s a fairly unique concept, and while the price may seem a steep to some (NZ$5) on a platform with so many free to play games, it’s a fun little game. The shooting from behind concept reminds me of Downwell, another fun arcade style shooter.