I remember back in the day being fairly unimpressed by Icon of Sin (and Spider Mastermind, since I thought the Cyberdemon had a cooler design, took more hits to kill, and did more damage). But that Brutal Doom version looks awesome, I must give that a try. Right now I've finished playing through the vanilla versions of Doom and Quake with the classic control schemes, and halfway done with Doom II so far. 
  ShadowWulfe: That one is Activision though right? Good luck getting them to let go of anything. 
  Hmm, I thought so too but I just checked Steam and it's published by Bethesda there:  
http://store.steampowered.com/app/2210/ 
 That actually gives me some hope for Heretic II coming to GOG, maybe it needs their touch like Battlespire and Redguard did.