A 3D, sim-like arcade helicopter-shooter tower defense. Repair, re-arm, and upgrade your heli at the FARP as the battle permits. Three flight physics modes provide a stepped learning curve and wider accessibility, and the tutorial mode provides a safe learning environment.
The National Laboratory has been studying all kinds of crazy biological "tools", and now it's under invasion. If any of that research gets captured, or worse, some sort of vector gets out, it could be the start of a happy new world. For zombies. For us, it would be quite inconvenient.