This is Dr. Plummet's House of Flux by MicroIllusions for Commodore Amiga.
It is NEW, SEALED.
No one else is selling it NEW on eBay.
The lowest used price is over $69 plus S&H. There best one is LIKE new for about $140 with shipping.
Description:
In Dr. Plummet's House of Flux the player has to man a small space ship to reach Dr. Plummet, a mad genius whose inventions are needed to stop an incoming alien invasion. The game has 28 levels (divided into four difficulties) which are solved by saving seven stranded pilots which previously failed the same mission.
The gameplay of this game is similar to Thrust: the most grave obstacle is gravity which may change from level to level. It causes the ship to steer into a certain direction and the player needs to counter steer so it does not ram into the environment. The player can freely rotate the ship and use the thrust to get a boost. The gun is used to destroy alien turrets which shoot at the ship and are mostly stationed near the astronauts. The fuel reserve gets drained when the thrust is used or if the shields have to fend off an enemy shot - reaching zero causes the loss of a life.