Chair Up! V0.11

Git commit: 13a3bcf41219fa9cd892a3ab843623a78154cf4b

Bugs Fixed:

1. Fixed the bug that player cannot respawn correctly when brake buttons are pressed.
2. Fixed the bug of the camera's moving and zooming.
3. Fixed the bug that the chairs can't drop correctly.

Polishments:
1. Add countdown to the Don't Be Late level.
2. Reduce the number of desks in office.
3. Reduce the UI background transparency of customers' call.
4. Add a cool down time to the character kicking actions.

Refactors:
1. Refactored the level class for preparation of later developments.

Play Video:

修复Bug：

1. 修复了玩家无法正常复活的bug。
2. 修复了相机的移动和缩放的问题。
3. 修复了场景中椅子坠落没有重力的问题。

润色：

1. 为抢电梯关卡增加了倒计时
2. 减少了抢电话关卡的桌椅数量，给玩家更多空间。
3. 减少了客户拨入电话时的UI背景透明度。
4. 为玩家踢腿动作设置了冷却时间，避免玩家多次蹬腿后速度过大。

重构：

1. 重构了Level类，使后续关卡开发更加流畅。