Suikoden II is on the list because of all the beautiful spritework. Especially in the early-game, there are numerous events that use sprites that are only seen once in the entire game--the best example being when Viktor and Anabelle share tea(?) and there are tons of sprites of both of them drinking and making minor idle motions that aren't used anywhere else in the game
Metal Gear Solid is on the list because of tiny things you can do that actually impact the game, like how you can use the smoke from a cigarette to make lasers visible, or how enemies will notice your footprints, not just the obvious things