Alen Ladavac, CTO at Croteam, developers of the Serious Sam series of computer games, lashed out at the Windows 8 certification process, writing that it is a "broken concept and should be abolished" in a post on Steam's community forums.
Of the issues Ladavac takes with the Windows 8 certification process, the first he targeted is the fact that tiled UI applications in Windows 8 can only be released through the Windows Store, and not through any other channels. This essentially prevents users from downloading an application from the Internet (even a free one) and running it on a Windows 8 machine, unless it's through Microsoft's store.
Apps must be certified before appearing in the Windows Store. Ladavac complains that this is equivalent to "bringing the 'console experience' onto your desktop," and that all apps on the Windows Store will be subject to the whims of Microsoft's requirements policies.
Mature games like Skyrim, Call of Duty, and Serious Sam were originally banned from the Windows Store due to their content, though this policy has been reversed by Microsoft. However, these mature titles have not yet appeared on the Windows Store and likely won't until December at the earliest.
Additionally, modding has been forbidden by Microsoft's terms. "They could very well forbid Open Source if they want," Ladavac wrote. "But even if these terms were not there, this is still a certification system. With all of its downsides, including uncertain release dates, rare and late patches, and everything turning out to be more expensive and sucking more."
Source: PC Gamer