1. Complete the performance optimization of zombie movement. A wave of 100 zombies can run at 90 frames.
2. Complete the zombie generation logic and improve the game entrance
3. Change some UI buttons
See More：https://www.bilibili.com/video/BV1fH4y1w7WT/?vd_source=74ba105a279f4568a119a1661fac6ff0#reply230191722256