Good question. The policy is explained at the bottom of the Submit page:
By uploading a game using this form you agree that you are the author of the game, or their authorised agent acting on their behalf, and that you have obtained full permission to use any copyrighted materials contained within it. You agree to allow Axe Software a non-exclusive licence to distribute this game on the textadventures.co.uk website and in any other form.
So:
- you must be the copyright holder to upload a game (or have permission from them)
- you keep the copyright
- we can distribute the game via textadventures.co.uk and anywhere else
The "and anywhere else" bit means for example, as in the current version of Quest, your game might be included in the download.
There's no automatic option for taking the game off the site, but you can always email me to ask that your game be removed and I'll take it down.