A merge-defense ad built around one visible power jump: weak cannons, a merge, and a lane that suddenly clears.
Tap a cannon to select it, then tap a matching cannon to merge (LV1 → LV2 → LV3) or an empty deploy slot to place it. A deployed cannon can also absorb a matching upgrade. Enemies march from spawn toward the base; the deployed cannon fires automatically, and LV3 fires piercing shots that hit every enemy in the lane. The final wave brings a boss.
Make the upgrade legible without text: the same lane that LV1 barely holds is cleared instantly after the merge.
The shipped playable ad: one authored encounter — merge matching cannons, deploy the upgrade and hold the lane through the waves and the boss.
The standalone build runs three levels from a start screen: a 2×2 training bench with one deploy slot, then a 3×2 bench with two slots against escalating waves and a boss, then a 4×2 bench. The third clear ends on DEFENSE COMPLETE with PLAY AGAIN.