Xbox Live-enabled games are prominently featured in the Windows Phone Marketplace--perhaps promoted too heavily, making it less obvious to users that lots of independent games without Xbox Live support may be worth checking out. The Live-enabled games currently range from $3 to $7, and while most are a good bargain, some prices leave me scratching my head (Bejeweled for $5? It's $3 in the iPhone App Store).
The majority of paid apps for Windows Phone 7, games or not, have free demo versions. Demos operate a bit differently here than on iPhone or Android (where a demo is a separate application, making you head back to the store to download the pay version if you like it). Rather, trial versions operate as they do on the Xbox 360: You download one complete app with a free "trial mode," and if you want to buy it, you simply unlock the software you already have. This model is definitely superior.
It will take two things to rectify the relative dearth of top-tier games on Windows Phone 7. First, developers need time to port their popular titles to the new platform. Apps are piling up rapidly for Windows Phone 7, and a lot more games will be on offer over the coming months; but high-quality development takes time, and this is a brand-new phone platform. The second, bigger issue boils down to raw hardware-sales numbers. Developers go where they're likely to make a good return on investment. If Windows Phone 7 devices fly off the shelves for months on end, developers will flock to the platform. If Apple and Google remain overwhelmingly dominant, Microsoft will find it hard to persuade developers to support the new platform.
One huge gaming advantage for Microsoft's new phone platform is its connection with the popular Xbox Live service. Well over 20 million Xbox Live members are buying games for their , and even more people play PC games that use Games for Windows Live. This is a built-in community of game players who are each invested in a single Gamertag (a person's online identity on Xbox Live) and addicted to earning Achievements to build up their Gamerscore. They have cute, cartoony avatars to visually represent themselves, and they already have friends lists of fellow gamers.