Diablo II has the "look and feel" of Diablo I but is an entirely different game.  It consists of 4 acts, each act with it's own quests, NPCs and monsters.  The graphics are simply amazing, although the game is only  available in 800x600.  It is MUCH more challenging than Diablo I ever was,  and there are different levels of difficulty (Normal, Nightmare, Hell).  The item variation is also incredible, with hundreds of items to find and  collect.  If you're planning to play multiplayer, you'll also be happy to  know that it is IMPOSSIBLE to cheat in Diablo II.  The Battle.net  "realm" characters are stored server-side, eliminating all ways  of cheating.  This is the best game of the year, and is easily worth your  money.