Working Tower Defense thingy. (WIP)

I'll fix the description later. My brain is dead. Please like this level and tell me any help in the comments for the Altar's level system and other suggestions.
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The green altar indicates the availability to upgrade, once it's blinking continously, it means you can upgrade one Turret already.

The turrets [inspired by HEKPOH(?)] will hit all enemies. Upgrade the turrets' damage by tapping on them.

The Castle is where the enemies spawn, the house is what you have to protect, while the score indicates your life.