Move with one hand, aim with the other, and hold the fire down. Enemies arrive from the edges in patterns rather than crowds, each type moving on its own rules, and the screen fills up faster than seems reasonable for something this small. Powerups drop and are gone in a second if you do not turn for them.
It is loud, it is fast and it has the specific quality of the good arena shooters, which is that dying always feels like a decision you made three seconds earlier. It saves your score and your settings between runs. Sessions are five minutes. You will have several.