Exerion

This is a shoot-em-up game with parallax effects in the background. It does have a simulation of inertia in the control of the ship.

There are dozens of enemies and two types of shooting: slow and fast. Two weapon systems: one slow double-shot cannon and one fast single-shot cannon.

With each enemy hit by the slow cannon you get one shot added to the fast cannon ammunition supply.

A challenge stage follows each stage in which you can build up your fast-shot bullet supply.