I've been a bit absent lately, as I've been heavily invested in a project. >>>/vr/
's Doom/FPS General is doing a mapping project for Doom, the rules are to make it in Boom format, and the level has to fit within a 2048x2048 square (generally). The deadline was first on the 18th of July, and was then extended to the 26th, and I've been very busy building ever since.
Started out with one map, one which doesn't strictly fit the 2048x2048 criteria like it should (thus assigning it to the 'reject pile', which will be included as a side thing), and I spent all time until the 18th just building that thing. When the deadline was extended, I figured I'd do another map, then actually sticking to the 2048 limitation, and I found that it was actually a lot quicker and more straightforward.
To expand on the limitation, a kind of speedmapping project which used to be popular on places like Doomworld was a 1024 project, which would be a map where the playable space fits inside a 1024x1024 square (anything outside of the playable area can be as big as you want), this would be a pretty small map, and the challenge was to make something that was good which fit inside that constraint. These projects were done often enough that people got sick of making them, and people got sick of playing them.
2048x2048 would thus be double the space, and what I've found as I'm mapping is that it's actually a very comfortable limit, it lets you do quite a lot more than the rather tiny 1024, but it's not so big as to let you get completely carried away, because sooner or later you will start to run out of space and you force yourself to make the map end.