I know this is the main thread and not the snapmap thread but I wanted to crosspost and share how much work goes into making a full fledged map.
I've created a reimagined Doom 64 Level 1 with 10 secrets and an ending fight. I really enjoyed Doom 64, although people's feelings on it are mixed(mainly on the music being more scarily ambient instead of metal).
Check it out here: UMRLCE7N
This is a sample of the map. It's almost accurate to the original.
Creating a full fledged level is really, really involved work. I felt like I was actually working for id while making this. There are so many variables to consider, what happens when a player dies, what spawns where and at what time, what to take away and what to add, making sure there is enough health and ammo, making sure the player isn't overwhelmed, making sure a creature in a room way in the distance doesn't run towards the starting area, making sure music works, sounds work, making sure secrets have just enough of a noticeable hint.
One thing that didn't help while making this was the fact that they put a limit on enemy spawns. For example, consider if a player didn't fight at the start and ran past your enemies to other rooms, if the enemies are still spawned in the previous rooms, the game won't load the next enemies that it's supposed to and the player can just waltz right through your level, no issue. You have to create 'if statements' to cover all bases so your level isn't cheated. You also have to create if statements so that the older enemies spawn again if the player backtracks, but the ones that are dead should remain dead. This limitation really sucks and I hope they remove it in the future(framerate be damned), because most of my work went into this.
While making this and taking hours upon hours to do so it just made me respect id even more on making a game like this in 2016 since the easy way out really is corridor shooting or canceled Doom 4. They had the heart and spirit to go the extra mile and it paid off with the fans and the critics alike.