There are at least three serious choices here when it comes to ultimate impact on gaming, so I'm voting for my favorite of them, which was also my favorite game of '96: Tomb Raider. The case for Tomb Raider is very easily made: this was the game that gave us Lara Croft, the best-known and most iconic action heroine in all of video games to this day. And unlike certain other action-adventure games, people could actually tell that this heroine was female in trailer footage and on the box art. Tomb Raider's sheer breadth, rich atmosphere (with its strong Indiana Jones vibes), and maze-like level structure appealed to me immediately and still do, despite its reliance on some play mechanics that feel pretty outdated at this point. Perhaps even more impressive is the fact that it was by just six people, which just goes to show that it doesn't take a massive development team to craft a masterpiece. And that it was one was recognized immediately by the gaming community, as signaled by the fact that, even as a new IP, it became one of top-selling games of the year. In fact, if memory serves, I think it might've even been the top-selling video game in its actual year of release. They'd been aiming for just 100,000 units, for comparison's sake.
As a bit of pointless trivia, I actually got the Sega Saturn version of the game first since I wouldn't own a PlayStation until the next year. It was generally expected initially that the Saturn would outsell the PlayStation because of the familiar Sega brand and I didn't want to potentially be left out, so it had been my priority. Conversely, my decision to get a PlayStation the next year was driven by word that the PlayStation would be exclusive console home of Tomb Raider II and Final Fantasy VII: games I simply could not go without owning.
I also kinda want to give a shout-out to Super Mario RPG: Legend of the Seven Stars because that was my favorite Mario game, and I mean by a landslide, up to that point in time and would remain so for another eight years. Probably because it was by Square, really. Square and Nintendo seemed like such opposite institutions to me. One seemed to view games primarily as a storytelling medium while the other viewed them as pure entertainment more or less. I honestly have no idea how they became so close, but I'm really glad it did. 
And since we're on the subject of Super NES games from 1996, this seems like the perfect opportunity for me to shamelessly hawk my old thread explaining my thoughts on Dixie Kong's Double Trouble.
