Singleplayer Doom II map. Focus on vertical, interlocking layouts combined with classic Doom design. Download it here.
Created in a couple weeks, Toxic Complex was my first real attempt at level design. Doom was a good choice due to its simplicity and wealth of design critique to study. Before I put my pen to graph paper I had a pretty good idea of what kind of setpieces and pacing I wanted, as well as a ton of ideas for encounters and architectural shapes. The rest grew as I built the map out. I threw out whiteboxed levels and made the next one leaner, carrying on the best ideas.
Doom leans into its then-new tech by having varying levels of height. A good Doom level has areas designed as flowing, interconnected environments. This proved to be the most fun challenge since Doom's lack of a Z-axis means areas have to feel connected without overlapping.
My favourite moment in the map is when an earlier monster closet is revealed to be an elevator back to the beginning of the level, letting the player go to a new area that lets them platform over the pit they were just in. I think the result is something that maintains the philosophies of classic Doom while adding a modern style.