Only yesterday I discovered I could play an adventure game in emacs. Then I discovered a bunch of layers and modes that were awesome. I haven't begun to scratch the surface, but if I buy a new Nexus 6P can I just flash Emacs on it?
You do not need to flash anything. It's already available on Android phones even without root. I use it on unrooted Nexus 6p.
Google "Termux emacs".
+1 for Termux.
I started using it purely for the novelty of running emacs on my phone (a moto x pure) and it's a great piece of software. It's even open source!