Compiled reflective materials,Compiled reflective materials and fixed a bug with respawn points

The lab area was removed, more supplies were added, more respawn points were added, the number of obstacles in the scene was reduced, and the player's path was simplified.

修复实验室大门无法打开的bug，投掷物可以穿过空气墙，搬运物品任务删除

Fix the bug that the door of the laboratory cannot be opened. The missile can pass through the air wall and remove the task of transporting items

修复bug，添加一个可选的简单难度。
Bug fix, add an optional easy difficulty