Just screwed up my system, am I alright though?

So, I just tried flashing this on my Nexus 6P Android N after backing up "system". I did it, rebooted then all my system UI had dissapeared (nav bar and notification bar mainly) but I was able to use apps on my homescreen, drawer and everything. So I rebooted into TWRP restored my system with the backup I just made right before I did anything. Now I get the System UI has stopped responding and cannot do anything like before. What did I do wrong?

from xda-developers http://ift.tt/1rSM6BZ
via IFTTT