Microsoft's patterns and practices group wrote the book on web and desktop application architectures (literally). One of the sections in that book is application archetypes which describes the types of applications that you can build. This is useful because an ecosystem can spring up around each archetype (controls, usability studies, tutorials) which can provide a lot of feedback and guidance for new projects to follow.
To that end I wanted to start a list of the different archetypes that might be available to choose from when designing a game for windows phone 7. Don't confuse this with a discussion about game genres ... those are already well known and documented. This list covers types of applications, game mechanics, and input styles that you can use to directly affect your game's design in a fundamental way.
- The Mini-Console If you already have a game that you've written (using XNA for example) and you want to do a direct port to the phone, then you are writing a Mini-Console game. Games like this will generally be played in landscape mode, which gives the developer enough room to provide a virtual d-pad and button(s) on the bottom left/right of the screen. The idea here is that the user will feel like they are playing a handheld console like the DS or PSP.
- The ARG Alternate Reality Games are growing in popularity. They typified by involving real world elements in one way or another. This can involve using the player's real world lat-lon location to have in-game effects (using the System.Device.Location namespace), or using the device's camera as an input mechanism. I don't see much of these, but it's an interesting space which I hope more people will investigate.
- The Physical These types of games involve the user physically manipulating either the screen, or the device itself to affect the game play. Games like this have to take this analog data and approximate the user's intent in making that motion or touch. I often see games which should be mini-consoles try to use this type of physical input just because they can ... and it sometimes results in awkward gameplay. More research and testing needs to be done in this space to figure out what works and what doesn't. For an example of the types of things we should be thinking about, check out my article on approximating touch points.
- The Casual Casual Games are tearing their way through the game industry. Read this report from the recent game developer's conference for some of that commentary (http://www.designer-notes.com/?p=195). Regardless of which side of that divide you land on, I think one thing everyone can agree on is that casual games are here to stay. WP7's push notifications and asynchronous game features will be very useful for games like these.