Metal Gear 2 original boxart (source)

Metal Gear 2: Solid Snake was the second game released in the Metal Gear Solid franchise and the sequal to 1987's Metal Gear. It was released in 1990 on the MSX2 for Japan only, it wasn't released in Europe and North America until 16 years later when it was bundled in with a special edition of Metal Gear Solid 3.

It retains most of the stealth gameplay of the original but improves on the enemy artificial intelligence and the visuals.

Metal Gear gameplay screenshot (source)

You again take the role of Solid Snake as he attempts to rescue biologist Dr Kio Marv from Zanzirbarland. Along the way Snake must destroy a new version of Metal Gear and take on his former commanding officer in Foxhound, Big Boss, who is also revealed to be Snake's father.