[GAME] Starfox 64 (1997)
I'm always in favour of games that are very short but encourage replayability, with systems that change depending on your actions throughout the game. I think this is both a great use of the medium, as no other format of storytelling really lets you do this, but it's also a smart way of reusing assets while making the game feel fresh with each run through.
Starfox 64 does exactly this - the main campaign can be beaten in two hours, but there is a whole host of alternative routes that the player can take to increase or decrease the difficulty, as well as completely new bosses depending on what the player does. As a rail shooter, it's thoroughly competent, if nothing particularly outstanding, so it's the overall systems here that really impressed me.