I’ve been making levels for Doom / Doom II since around 2001.  All my released levels are available here for you to download (listed in reverse chronological order — newest first).  Clicking on the level title takes you to the information/screenshots page for that level.  You can also read what others had to say about the level in question and post your comments as well.

Levels for Doom II

1. Dark Fate 2
2. Reanimated
3. Metamorphism
4. Congestion Control 2
5. Dark Fate
6. Out of Phase 3: One Cloudy Afternoon
7. Congestion Control (Doomworld 100 Best WADs of All Time)
8. Out of Phase II
9. Out of Phase

Levels for The Ultimate Doom

1. The Hazard Variation
2. The Other Side of Phobos
3. Chaos Punch
4. ICK

Special/Experimental Levels

1. Simpler (Doom II; contains a cool trick where you get the yellow key after killing a mancubus)
2. Marbelus (The Ultimate Doom; uses the 666 trigger and the spiderdemon)
3. Karthik2 (Doom I; my first map)

Speedmapping

1. Doomworld Speedmapping Pack #4 MAP16 (Tech Base)
2. Doomworld Speedmapping Pack #5 MAP09 (Co-op/Outdoors level)
3. Doomworld Speedmapping Pack #16 MAP07 (Abandoned Mines) « good speedmap
4. Doomworld Speedmapping Pack #17 MAP05 (Canyon)
5. Sarge Baldy Speedmapping Pack #19 MAP01 (Based on favourite level) « good speedmap
6. Sarge Baldy Speedmapping Pack #20 MAP03 (Sewer level) « good speedmap