Level design was kinda fun back in the day of Quake/Half-Life/Unreal. Professionals or amateurs with enough skill can push out a good looking level in a few weeks to a couple of months. A good team of 6-8 amateurs can pump out a full map-pack (usually consists of at least 10 maps) in under 6 months.<p>Since the introduction of more sophisticated rendering engines level designing (and asset creation in general) has been pushed further and further away from modders or even professional themselves.<p>I'm not particularly sure whether this is a good thing or not, because nowadays people are still making maps and mods for legacy engines such as the first DOOM, first two Quake, the two Half-Life and UT99 (Unreal Tournament happened to contain all UnrealScript for Unreal and Unreal return to napali thus becomes the premium development platform for Unreal single-player modders, plus it has a better engine and more importantly a better editor). But when you go down the stream, the more modern the engine is, the more difficult to make mods for.