This is bad... First make a system monster, and then don't release any demo. Sorry but i don't pay full price for a computer game that may not run properly on my computer. I can't take that risk.
I love consoles for that reason.
And i'd suggest Mount&Blade but my signature is already doing that. You can play it for a pretty long time. I've played it about 100 hours so far.
So if you are interested in some indie games, it's a good one.