You should try reducing graphics to fastest, resolution to 640X480, running it in fullscreen, and closing all background apps.
Then, wait at least 10 minutes.
Maybe go to the kitchen and make some tea or a snack before returning to see if it has loaded.
Also, this is a very early alpha release as Ratchet said. I doubt it has much optimization at all in its current incarnation.
The fact that they list 640X480 as a resolution that exists makes me think it's going to be pretty well optimized for lower end computers.
If none of those things work, maybe you should give this program