Oh, god, what a year it was! Really hard to judge what is "best". What criterion would one even use after all these years? Long term industry impact? Personal time played? Quality of art/music? Achievements in programming? How did it age? No idea, really. Also nostalgy doesnt help at all.
As a mostly PC player back then I missed on many gems, some of those I was able to experience only relatively recently, so it also skews perspective. Hopeless, but I try anyway.
1. DOOM. Well, it is the game for which I installed an over-the-air coaxial cable connection to my neighbor so we could play it regularly. Distributed as a shareware over Fidonet which helped to propel its popularity to cosmic levels and created all that modern market for FPSs.
2. Day of the Tentacle... Sleepless nights, several months of puzzle solving/guessing/desperate pixel hunting. Still remains one of the best adventures of all times for me.
3. Mortal Kombat. If Doom was the king of LAN parties, MK was the go to local multiplayer at that time. Bloody good times.
4. Master of Orion. This came in like a comet and ate those night hours like it was nectar. I just gotta sent some colonists on that planet so they can repel the invasion, let me count the turns.... What, it is 3am already?
5. X-Wing. I do not think I'm only one here who bought a flight stick/joystick for this game and didn't regret it. Space sims would probably be much less popular today if not for X-Wing/Tie Fighter nostalgy.
6. XCOM. I thought it came out later, but maybe USA version did come out in 1993. no idea. Anyway, this game introduced my young soul to "addictive punishing", the feeling I forgot I like until Demon Souls came out. Only I had way more time back then to bath in it.
Honorary mentions:
x. Secret of Mana
x. The Lost Vikings
x. Sam & Max Hit the Road
x. Prince of Persia
x. Flashback
x. Disney's Aladdin
Yep, that was a good year. Diverse lineup, bold experiments, network play and 3D graphic advances. Good year indeed.