The apk is good to install yes. Just select it with something like root explorer or just open it in a mail on your device, you do have to select somewhere in the options to allow apps from outside the market.
Since I'm not very good with coding I don't think I can improve much (all the code is from SE). I do wonder why SE didn;t put this in the service menu though.
I to find that bothersome, walking goes fine but for aiming we need to sweep :/
SE Xperia play on stock rom with doomkernel.