1st-perspective shooter where you fight the other ship(s) and avoid each others traveled path (or shoot it).

Left-to-right scrolling shooter from http://www.asahi-net.or.jp/%7Ecs8k-cyu/index_e.html.

A 2-D boss' VS ship shooter.

Another cool Robotron 2084 clone found at http://www.binaryzoo.com/.

Preferable played with a dual stick controller if you have one.

The last Robotron clone on the list. Version 5.4 was the latest.