Defender Z is free and fun to play.

Use explosives and gravity to defeat evil invaders.
Plant munitions under enemy tanks to blast them up high into the air.
Then gently nudge your device to 'guide' the enemy into the Kill-Zone and keep them there, until the snipers can do their job.

There are hundreds of short missions with increasing difficulty.
Every successful mission will add to your score as you advance through the ranks from Lieutenant to General.

For highest scores, plant your explosives wisely. Fewer blasts will save ammo, which is a bonus. Some missions may be possible with a single, well positioned blast. Try to pop a few enemy Generals on the way for extra points.

Scoring:
Complete enemy standstill in Kill-Zone => Mission accomplished
Each Ammo saved => 1 Point (main bonus)
Each General killed on the way => 1/3 Point (a little extra bonus)

Enjoy!