There was a time when mods where so good that they bloom into a full game like a flower.Sadly that was a decade ago called the 90s.Here we are in the late early 2000s and I ask you what ever happen to the mods that made people buy a game that they never played but just wanted to get it just because of a mod.The mods i see today for some games i can say are kinda the same for instance Half-Life 2 is it kinda weird that half of every mod in that game is a vs or that the scripted movement of the player,the game play is bland,or you just don't get it why that everytime I hold a melee weapon its over my head as if I am holding a CROWBAR possibly it is just the same as playing Half-Life 2.Now you can disagree with me on what I said.There are hopefully some mods left if there is a mod left that is so unique fun and great.That it will one day have its own cover with a box art on it and a publisher.The new step i see in mod making that I like is the remake of a game that already made so we can just remake it in a new engine and so, for instance Black Mesa Source or Operation Black Mesa are remakes of Valves hit games Half-Life and Opposing Force.Now that to me is something new a mod that is a remake of something I once played but see it in a different engine and gameplay so remember those mods that did the whats now impossible Team Fortress,Day of Defeat,and Counter Srike.By the way those 2 mods I said I already know there not EVER going to become games.Don't Forget about making a mod about a game that hasn't have a sequel out yet like Opposing Force 2 or Blue Shift 2.Maybe on day your mod will become a full game 
