There's a problem with a specific texture that doesn't want to play with WebGL. I'm not sure how, but even removing the texture doesn't solve the problem, although I don't think it's a cache problem; going back to a previous version (in which the problem didn't occur yet) completely solves it.
Will add a .exe soon, though for Linux setup isn't helped by that.
We're planning a playtest very shortly, so our priorities are on that at the minute.