Taleworlds are offering Mount&Blade through a try before you buy model. You can download the game and start playing right away. What you download is not a demo, it is the full game. There is, however, a level limit at 7. When your character reaches level 7, you can start a new game or, if you decide you like the game well enough, go on and buy a license online. As soon as you buy a license you will obtain a serial key which will remove the level limit. You will not need to download the game again.