Rampart is an unreleased Atari 7800 prototype. Being a prototype, details on gameplay, original features, and developer remain obscure. The ‘Unknown’ and ‘Proto’ designations point towards this being an unfinished or unreleased game found within the Atari 7800 development archives.  It might represent an early version or a concept that didn't reach full development and release.

Rampart (Unknown) (Proto)

Pole Position II (Europe)