| Title | Author | KB | Genre |
|---|---|---|---|
| U.N. Commando Episode 1: Guerilla Warfare | Unknown | 12.02 | Action |
| Uddie Blade:I | Robovine | 77.49 | Adventure |
| UFO | Erik L., kristomu | 12.78 | Action, Adventure, Incomplete |
| UFOs: Invasion USA (v2.0) | Transon | 11.99 | Adventure, Shareware |
| UFOs: Invasion USA (v3.0) | Transon | 12.73 | Adventure, Shareware |
| An ugly demonstration of the afterdeath movement bug thing. | Nanobot | 0.8 | Help |
| Ultima RPG | Ultima | 49.27 | Action, Puzzle, RPG |
| Ultima RPG 2 Demo | Ultima | 15.67 | Action, Demo, RPG |
| Ultima Rpg Demo | Ultima | 24.33 | Demo, RPG, Shooter |
| UltimaRpgDemo R.I. version | Ultima | 26.28 | Demo, RPG, Shooter |
| The Ultimate Arena | Nzenik | 15.6 | Adventure |
| Ultimate Conquest (Sneak Peek) | Unknown | 2.67 | Adventure, Demo, RPG |
| The Ultimate Game | wonder | 12.49 | Action |
| Ultimit-X (X-Men 4) | Unknown | 10.73 | Action, Fangame |
| Ultra Blaster | Unknown | 4.52 | Action |
| Ultra Toolkit | Nanobot | 58.51 | Toolkit, Utility |
| Ultra Wack | Zenith Nadir | 49.78 | Art |
| Ultra ZZT Magazine | Robo Bagle | 243.85 | Magazine |
| Umber2 | Bark P | 6.41 | Action, Engine, Puzzle |
| Un-ZZTAE | CyQ | 34.41 | Utility |
| Unacceptable Risk | davr0s | 8.04 | Action |
| Uncle Murrie's Bloated Animal Funland | Kurisu-sama | 18.63 | Adventure |
| Under World Legends | Emon | 14.53 | RPG |
| The Underground Bugtown of ZZT (1993-02-17) | Alexis Janson | 23.29 | Adventure |
| Unfair!! | Steven Backus | 8.37 | Action |
| Unfinished Business | Rasconza, Ringworm | 164.8 | Compilation |
| Unga Khan 4 | Dynamo01 | 36.62 | Adventure |
| The Unknowable Timothy Billings | Dr. Dos | 9515.72 | Horror, Story |
| Unlimited Maze Works | Lancer X | 37.25 | Adventure, Dungeon, Maze |
| UnLockPRO | Kev Vance | 20.99 | Utility |
| UnlockPRO 2.0.0 | Kev Vance | 18.14 | Utility |
| The UNOFFICIAL ZZT Programming Guide | Corey "Des" Garriott | 31.37 | Utility |
| Unreal Animals | Creative | 10.86 | Engine |
| Unreal Arena | Snuffalufucos | 16.17 | Action, Demo |
| Unreal Arena | Snuffalufucos | 24.53 | Arcade, Shooter |
| Untitled | Unknown | 1.59 | Experimental |
| Untitled Walking Simulator Demo | Agent Orange | 16.12 | Demo, Other, Story |
| Unusual | WiL | 17.22 | Trippy |
| Unwoven Pixel | Noser | 14.54 | Action, Engine, Experimental, Remake, Trippy |
| The Uprise (Modified) | Aetsch, Zenith Nadir | 23.26 | 24HoZZT, Action, Contest, Mod |
| Upside (Demo Version) | BroKen | 9.1 | Demo, Platformer |
| Upsidetown | Dr. Dos, Tim Sweeney | 24.72 | Adventure, Experimental, Font, Remake |
| Ur Mom's Cheerio's (AKA Super Ugh) | Viovis Acropolis | 42.42 | Action, Trippy |
| Urinade | Mrs. Claus | 211.35 | Magazine, Trippy |
| Urk | Ian McMahon | 53.8 | Action, Adventure |