1. Play game and complete tutorial.
2. Open root explorer
3. Go to: data/data
4. Delete com.glu.modwarsniper
5. Download the mediafire file
6. Extract it and go to extracted location.
7. You should see a com.glu.modwarsniper file.
8. Press it once. There should be another com.glu.modwarsniper file inside.
9. Copy the com.glu.modwarsniper file inside.
10. Paste it in data/data.
The reason why I say delete first is because sometimes, when replacing with the hacked file, the hacked file got placed in the original file, so the game can't read the data and will fail, force close.