Post vastly more information. We're only mildly psychic; describe exactly what's going on here. Is there an error, and if so what exactly does it say? (down to the number, if given) Does it stall, and if so when? Did you run the updater, and if so
read this. If that thread doesn't help you post your system specs, namely your CPU, graphics card, RAM, etc.
Officially we call it a "pre-alpha tech demo"... which is an excessive force euphemism for "we have bugs".
Yes, we've got a little C in there, but it's mostly C++.