Bitmania

Bitmania is a vertical scrolling shooter where you move around a screen destroying as many Bits as you can on your journey to the Central core of your Commodore 64. Your ship is inside a data-bus amongst the Neuron Flow and you must keep shooting the Bits and when shot they leave behind a Pod which also needs shooting over various waves. Once you have shot enough Pods then you move to another wave but if you are hit by a Bit then you lose one of three lives. Before the game you can select the speed (1-3) with one being the slowest, and the skill level (0-29) with the higher skill levels having more Bits on screen.

Source: TheGamesDB