Silent Assault is an unlicensed game developed by Joy Van and published by Color Dreams in 1990. In this game, an alien force has somehow taken control of all of Earth's military forces. However, the player character is not under the alien power's control, meaning he's the only one who can fight back. Said character now has to fight through enemy military and alien forces over the course of 8 levels of varying awfulness.
The author of this TAS runs through the game in only 5 minutes and 26.91 seconds.