Some missions require you to use a certain weapon type (the first is mission 4, a heavy-machine-gun mission). So don’t focus just on one weapon type, but instead gradually build and upgrade all weapon types.
Mobile Gaming eGuide - Tips, Tricks, and Strategies for Today's Hottest Mobile Games Unkilled
Some missions require you to use a certain weapon type (the first is mission 4, a heavy-machine-gun mission). So don’t focus just on one weapon type, but instead gradually build and upgrade all weapon types.