I thought about this quite a long time, but finally I decided to try and make a demo version of The Miners. I was worried about successfully limit my game without any injury to game code, but I think I manged to do this.
The Miners Demo contains 2 playable races and 2 maps (+tutorial map). Additionally some achievements have been allowed. It provides good view on a gameplay before you make a final decision to buy a game.
You can download it at IndieDB on below link.