Watch out, intruders will be stronger and stronger.  New BOSSES will come out as stage goes.  Be the hero, and win the HONORS! 
Any suggestion/feedback is welcome! 

What's in this version:
1.  Add a sound effect switcher and optimized the effect playing on certain devices. 
We found some devices such like HTC EVO 3D, Samsung Galaxy S2 have some issues on sound playing. 
Please turn off the sound effect if you have this problem. 
2.  Higher skill levels are available now. 
3.  Bug fixes.