1. There is a program called UKTUBE that comes with the UKMP media player. It has support for some flash video sites. It uses MPlayer for the playback. I believe MPlayer will play some wmv-files, but it's not optimized for playing them, so they might play very slowly, especially on 770 which has a slow processor. But i think it's possible to just paste the url of the wmv-file into MPlayers address bar.

2. Some linux games can work on the tablet with just a recompile, but for them to work properly, they need to be ported to the device. There are plenty of games available and they are very easy to install, just like normal applications.

3. I don't recommend using Hacker at this stage. Try to get familiar with the device and maybe try it later. It has it's ups and downs.

I recommend you spend time reading this forum and use the search function a lot. It will help you. To install software/games, go to http://gronmayer.com/it and install repositories to your application manager. That way you have plenty of software to try out, all from the application manager. Good luck!

ps. Be sure to install the wlan bug fix to your device to make it more stable.