For the most part we went from running the game at 320x200 or 320x240 to 640x480 in that first round of acceleration. I think in terms of % change it is a bigger leap than anything we've really had since, or certainly after 1920x1080.
So you suddenly had super smooth graphics, much better looking translucency and effects, and the # of pixels quadupled or more and you could just see everything so much more clearly.
I remember back in 1997, when Quake 2 was just out, I sit in a net bar (where you pay to use a computer) and played an hour of Quake 2 in software rendering. The game was interesting, but I felt a bit sick, half due to the resolution, half due to the almost infinite brownish colour. A girl behind me murmured, "This is not as half fun as Duke Nukem", and yeah I completely agreed with her.
I think I still agree with her somewhat. Quake 2 is a great game, but Duke3d is a fun one.
Quake2 was released at just the right moment to take advantage of both 3D acceleration and broadband Internet access. Playing a game of q2ctf, in 3D-accelerated 800x600 mode, with 60 ms ping was just fucking amazing.