Kindle Fire Web Browser will likely allow for web based games.
From what I have read of the Kindle Fire Silk Web Browser it appears it will be very fast and enhanced by Amazon's own servers.
Thus, it should be great for playing games at web sites which do not require a client download.
One such game which I have been playing for a couple of years is Ferion. I can hardly wait to try it on my new Kindle Fire this week.
For Multiplayer the web based space game of Ferion is far better for Multiplayer contests with a game server of It's own and minimal graphics to slow it down. It allows up to 50 players or more to play at once with each participating at times of their own convenience. It lasts for about one month and is turn based with moves processed 24/7 each hour. It is free to play if one accepts ads on the various game screens. To eliminate the ads, one must pay a nominal fee.
That game also has a novel feature. If you are in their server for 14 hours in any 24 hour period, you receive a warning. If you are in their server for 16 hours in that same period, you are banned for 8 hours to get sufficient sleep to protect your health. Civilization is very addictive as well and should provide a safety feature as well for time spent.
Other browser based games should work real well on the Kindle Fire as well as games played inside Facebook. This Kindle Fire could revolutionize our entertainment possibilities.