Space Defense Grid — is a tower defense game. Enemies in the game will attack the energy center, steal energy, and then run away. Players need to build a defense grid according to different levels. It should be noted that different enemies have their own characteristics, for example, some enemies gain energy and accelerate to run away, or open an energy shield. Players need to specifically adjust the mesh, in addition, the game designs the enemy’s shield and weapon armor penetration. For example, armor penetration of weapon A is 3, enemy B’s shield value is 4, attacker B’s damage is reduced by 10%, and the weapon’s range on the enemy is 10% — 100%.