About preordering, cancelling and beta, this thread http://forums.demigodthegame.com/326561 can be enlighting. There is an official statement in reply 6 in that thread:
If you simply decided you don't want it though, we can only offer 75%, as sales noted (their word is as official as anyone's, btw). While in the former case we're potentially at fault and will gladly offer a full refund, in this case, well, we can't guarantee everything will be to everyone's taste; if you're hesitant about a beta, you've the option to wait for word from others rather than jumping on at the first chance. Betas are not free demos. The game at this point is prone to issues and is very subject to change, and if you have some non-technical complaint with the game, you have the opportunity to try and get that changed before release.
For anyone else reading this, let me be clear: if you're hesitant about plonking down the money for the game before it's done, or are just looking for a demo and don't care to participate in the beta, then by all means, wait before preordering (in the latter case, better to just wait for the post-release free demo). You won't hurt our feelings by waiting to see how it turns out, and you'll save yourself some trouble in the event that you'd have found it to be just completely unlike what you hoped.