You're going to have trouble with rule no.2 and maybe add some more achievements, adds some flavour to the game (you have your opportunity to persuade them to playing the way you want :>). Also you should probably clarify the achievements part, if they're one-time rewards (as i suspect) or not. The achievements part is where you can let your imagination go a bit wilder, so don't stick with just 3. Looks good overall.