Okay so I tried to make a mansion... again. And I failed... again. The game crashed twice because I placed too many not-blocks, so I gave up on the mansion and perfectly recreated Mount Rushmore... sort of.
I had a lot of fun playing the game! I personally didn't encounter any significant glitches. The only thing that went wrong was the game crashing while building the mansion, but I like to believe it was the universe trying to save me from my own mistakes.
The game runs smooth, I didn't randomly fall out of the world and the game has an automatic system that saves stupid people like me from making decisions they're gonna regret. Great job on this one! ;D