The currently available version is Eschalon Book I, and you can download the demo from the official website. To start the game, uncompress the tarball and run it as ./Eschalon\ Book\ I\ Demo from a terminal or just double-click the Eschalon Book I Demo executable.
The game uses OpenGL and a native resolution of 800x600, which is also the only resolution available. It can be run in either windowed mode or fullscreen.
The Launch menu - you can select the graphics renderer and toggle the windowed/fullscreen modes here
Upon starting a new game, you will get to choose a character, including its origin, axiom and class (e.g. healer, rogue, fighter etc.). You can also spend skill and attribute points for adding certain skills or increasing attribute. For example, you can buy skills like Light Armor or Survival for 3 skill points each, and increase attributes like Strength, Speed or Wisdom for 1 point each. After selecting your character and deciding on what to spend the points, the actual playing part begins.
The character editor - choose a character and spend skill and attribute points
Playing the demo
In my opinion, the major drawback of Eschalon: Book I is the low resolution. 800x600 just doesn't cut it anymore these days, and it can look a little ugly on big screens or too small when ran in windowed mode. On the other hand, the good thing is that Eschalon provides a demo. Book II is also on its way, and, according to the homepage, it will provide a native resolution of 1024x768.
As a conclusion, Eschalon can be a good solution for those who like RPG games and don't care about a high resolution. The price is not high, it comes with a manual in PDF format, and it's addictive once you grasp the way to play it.