There wasn't much you did wrong, in fact it was perfect from a stabilization/maintaining lucidity standpoint. The only part you should've changed was when this shadow figure appeared. I understand it was one of your first times dealing with something like this but all you needed to do was make him go away. Whether you just made him disappear with your mind or if you got a weapon and had a fight with him is up to you but just do something, don't let him smash into your house and knock you down/wake you up. However it's likely the dream was going to end anyway. You said you woke up in the same position he knocked you down into and moving around a lot. This was most likely just your body getting out of SP/waking up and you kicking around woke you up.

As for the feeling you experienced that's pretty much what a very vivid lucid dream feels like. The almost omniscient or "sentient" feeling is just everything going on in your dream world being in your head and you technically knowing everything in that world. It's the feeling that makes LDs so amazing and incredible (that and the fact that you can do anything with no consequence )