Jumpjet DOS

Jumpjet is a 2D side-scrolling shooter game for MS-DOS, created by Monte Variakojis and released under the name Montsoft in 1990 as shareware. It is visually similar to Defender. The player controls a Harrier-like jet that can gain or lose altitude without moving side-to-side. The player fires missiles at his targets. There are four levels, each with a different objective. There is also two bonus levels that can be accessed with a high enough score in levels 1 and 3.

The core of the game is written in Assembly language, while the menu system is written in C.

- Wikipedia