There's been a deluge of classic games making their way to Android smartphones and tablets lately, and it appears there's another one on the way..though it won't be coming through official channels. Some enterprising developers have ported Valve Corporation's Portal over to Google's mobile platform using the Unity 

development environment and game engine (Unity is also used by Android games like ShadowGun and M.U.S.E.). This is still very clearly a work in progress ..it's listed as version 0.004 Beta ..so the glitchy performance is to be expected, and it's certainly not sanctioned in any way. Still, we can't help but get excited at the prospect of one day carrying an official Portal port around in our pocket.