Game crashes, won't start / Lua error?

So, after recently having updated to build 150626, i have run into this error:

I have tried verifying the game cache on steam twice, and tried reinstalling it. None of these things have fixed it.
And hit OK on the error, the game will show the initial black screen, with the red bar, with "loading" in the bottom, but freezes entirely.
The logs doesn't seem to update or catch this, so they're not much use.
So what seems to be a way to go about fixing this?

I have tried verifying the game cache on steam twice, and tried reinstalling it. None of these things have fixed it.
And hit OK on the error, the game will show the initial black screen, with the red bar, with "loading" in the bottom, but freezes entirely.
The logs doesn't seem to update or catch this, so they're not much use.
So what seems to be a way to go about fixing this?