25 wads
| File | Name | Author | Iwad | Demos | Length |
|---|---|---|---|---|---|
| ohman | Oh, Man! | Marius | doom | 4 | 12:37 |
| ohno | Ohno Ver 1.1 | David B. Cox | doom2 | 1 | 3:13 |
| oitl | Orange Is True Love | Ribbiks & Grain of Salt | doom2 | 36 | 3:46:10 |
| ojdoom2b | O.J. DOOM II (version ... | Wayne Poe | doom2 | 1 | 0:34 |
| oku2v31 | oku2v31 | Okuplok | doom2 | 12 | 31:45:04 |
| old_still_life | Old Still Life | Rednov | doom2 | 1 | 8:50 |
| oman | oman | Stian Skjondal | doom2 | 3 | 5:57 |
| omega01 | omega01 | Tomi Rajala | doom2 | 16 | 51:24 |
| omega_ii | OMEGA2 | David Davidson | doom2 | 1 | 2:28 |
| omelet | omelet | Malcolm Sailor | doom2 | 5 | 7:20 |
| omgpump | omgpump | PumpkinSmasher | doom2 | 2 | 5:39 |
| omgpump2 | omgpump2 | PumpkinSmasher | doom2 | 1 | 6:11 |
| 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 |
| ooe | One of Everything | Various | doom2 | 56 | 6:28:11 |
| 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 | 16 | 14:56 |
| ophase3 | ophase3 | Karthik Abhirama | doom2 | 15 | 24:40 |