25 wads
| File | Name | Author | Iwad | Demos | Length |
|---|---|---|---|---|---|
| omnomnom | Om Nom Nom | D0M0 | doom2 | 1 | 4:35 |
| one-humanity | One Humanity | John Romero | doom2 | 8 | 29:24 |
| oneonone | oneonone | Rich J. Sham | doom2 | 4 | 12:00 |
| oneweek | oneweek | Various | doom2 | 42 | 10:15:55 |
| onslght | onslght | Henri Lehto | doom2 | 1 | 1:15 |
| oops | Oops... All-Ghosts! | grapes | doom2 | 11 | 2:18:15 |
| oopsie | oopsie | Huy Pham | doom2 | 12 | 4:25 |
| op_801 | op_801 | Opulent | doom2 | 12 | 1:31:21 |
| openplan | openplan.wad | Dave Patrick | doom | 2 | 5:51 |
| ophase | ophase | Karthik Abhirama | doom2 | 5 | 8:52 |
| ophase2 | ophase2 | Karthik Abhirama | doom2 | 12 | 12:29 |
| ophase3 | ophase3 | Karthik Abhirama | doom2 | 15 | 24:40 |
| op-lite2 | op-lite2 | Stephen Clark | doom2 | 12 | 3:57:59 |
| opost21 | opost21 | Scott Amspoker | doom | 3 | 8:28 |
| oracle | oracle | Jim Flynn & Scott Harper | doom2 | 6 | 57:04 |
| orca | Orca | Jizzwardo | doom2 | 2 | 7:14 |
| ore15 | ore15 | Steve Johnson | doom2 | 2 | 0:26 |
| orifice | World Orifice | Benjogami | doom2 | 2 | 4:40:31 |
| origwad | origwad | Jeff Bird | doom | 50 | 30:26 |
| orin01 | orin01 | Orin Flaharty | doom2 | 3 | 4:04 |
| orpheus | orpheus | Shane | doom | 22 | 27:29 |
| oscl | oscl | Forli | doom2 | 2 | 18:53 |
| os-doa | os-doa | Philip Renshaw | doom2 | 2 | 38:54 |
| osiris | osiris | Glen Payne & Marshal Bostwick | doom2 | 6 | 27:37 |
| oskyrt | oskyrt | Hardcore_Gamer | doom | 2 | 14:40 |