Xecutor

The Zedar region of the Horsehead Nebula has been classified as “forbidden”.
Pilots of the Mark-7 Quantillion craft on route to the Stella Wars in Questron
Minor decided to put this definition to test. Even if they regretted their
decision later, there was nothing they could do about it: trapped in space,
surrounded by Zedar ships from all sides, the pilots realize they will have to
demonstrate their best skills in order to survive.

Xecutor is a vertically scrolling shoot-em-up similar to Master Blaster.
The player can either venture to defeat the Zedar alone, or play with a friend
who controls another ship on the same screen. The concept of the gameplay is
simple, but the game can be hard to master or even complete, necessitating a
memorization of the patterns in which the enemies or end-level bosses attack.
It can be controlled with either the keyboard, a joystick or any combination
between the two. Power-ups that can be collected upon the enemies’ defeat
include stronger weapons, additional fire power (up to three times the regular
strength), double and triple lasers, penetration missiles, explosive pods, and
shields.