Games bought from the site can be traded back in for credit. VVVVVV, for example, is currently on sale for £8.99 but can be traded in for £4.99 of credit at Green Man.
Green Man requires its own client, 'Capsule,' which uses SecuROM to activate and deactivate games. Capsule is needed to download and install games but they apparently will then run without it open. All prices are apparently listed in British pounds only for the time being, at least, and the only payment option is a credit or debit card.
89 titles are currently available, which COO Gian Luzio says is only a "small selection" from the 500-odd games Green Man has signed up from "over 26 publishers," used to test stability. More will be added to the site's catalogue "over the next few days."