The AWS cloudformation template on the site supports both PPTP and L2TP IPSEC protocol. So use as you like based on your security needs / device compatibility.
Also no websocket support in Android browser yet (http://caniuse.com/#feat=websockets). This makes things a little less ideal for realtime gameplay (even with the fallback options provided by socket.io).
Should also note that DeviceOrientation (aka "accelerometer in the browser") is in Android 3.0+ (although that doesn't do much for most of the devices out there).