Prior to v1.02 you could go to the Cow Level as many times as you wanted to, so if you really love it in single player, you could uninstall, reinstall Diablo II, and then play do the Cow Level with your open or single player characters as many times as you want to, as long as you don't upgrade past v1.01. As for the Cow Level itself, it's about what you would expect. Cows and more cows, called Hell Bovines , appear in huge, almost never-ending herds. Full stats for them can be seen here , on our hosted monster site, Darkness. By far the most tightly-packed monsters you see anywhere in the game can be found here.
Every cow looks the same, there is no variation in coloration or weaponry at all.
They all have massive polearms, and do quite heavy damage when they strike you with their very fast attacks. However their foot speed is very slow, and for that reason they aren't especially difficult to deal with one on one. The level is all on the surface, there aren't any sub levels or dungeon or cave areas, but there is a main wooden stockade sort of area, with walls just like those in the Rogue Encampment. Inside it's square-shape with openings on all sides, and a number of dead Rogues lying around, and others tied to stakes, as you often see them in Act One. It's not a real good place to fight in, since the approaching cows can easily fill every exit and you do not want to be cornered by them.