Update v20181217:
1. Clicking on the button will let the next wave of mosters come early.
2. Added a new mini-game: Eyesight training.
3. Added 2 more challenge where you can only use a limited number of towers.
 
Update v20181119:
1. Collect stars to unlock Skill Tree. It contains "Crystal Auto Collection"
2. Enemies in Easy and Normal mode are easier to kill now, and the items and energy crystals will stay longer.
3. Optimized the experience of the desert maps.
4. The size of the crystals will vary depending on how much energy they have.
5. The indicator will now automatically absorb nearby energy.
6. Increased the maximum of volume.
7. The bases where you can build towers are highlighted in the tomb levels. Newly unlocked towers will also be highlighted.