This app was mentioned in 8 comments, with an average of 3.25 upvotes
MFW you realize that since WC3 isn't open sourced, there will be no "Let's do that retarded 'run WC3 on something not made to do that' we spoke of while being drunk", but I think it's the nerd in me speaking...
If you have a copy of Quake 3 Arena for PC, get this app. You can map your volume buttons to shoot and jump or whatever you want. It supports multiplayer, and plays extremely well on my Nexus 5
You can actually get Q3 to run on android and it runs quite well on a modern phone.
wink wink
https://play.google.com/store/apps/details?id=com.n0n3m4.QIII4A&hl=en_US
There is another port with imho better control options in Amazon Play Store by Beloko.