The original Exerion was a vertical shoot ’em up released by Jaleco in 1983 and licensed to Taito for distribution on the United States. The game featured parallax effects and inertia simulation, something notable for 1983. [Info from Wikipedia] Sometime later, Jaleco worked on a “sequel” of the game, but as we can read on the Lost Levels forum, it was just the first Exerion with “updated graphics and music”. Anyway, in the end Exerion 2 was never released in America but a prototype was found and leaked online by the Nintendo Age community in June 2009. For all the NES collectors out there, a reproduction cart with Exerion 1+2 can also be bought and played on a real NES thanks to RetroZone!