CS was 3D shooter and not a DOS game - quite important distinction as it gave better(and nonpixelating) graphic. Pre 1.6 CS had many modifications already - frankly I stopped playing CS before 1.6 and had my fun.
Descent and Quake were both 3D shooters and DOS games, and Halo came out a year earlier with "better graphics"; CS was neither the first 3D shooter nor the first Windows game in its genre. Also, the first Counter-Strike was not a completely new game -- it used a modified Half-Life engine (which itself was built on the Quake engine).
Sure, CS was arguably the most popular and long-lasting of the FPS of that era -- but let's not pretend that that was because of technical superiority, it won out because of gameplay.
Sure, CS was arguably the most popular and long-lasting of the FPS of that era -- but let's not pretend that that was because of technical superiority, it won out because of gameplay.