* Add stories at the beginning and ending. Now you can see the great story the game is based on.
* Boss level is neatly completed. The scene is quite crazy and exciting. new mechanics included. Lots of new weapons are added on the boss.
* Add a machine gun progress in the last part of level 3. This part can prepare the players better for the boss level.
* Adjust the hardness of the first level. Mechanics are introduced better before players need to use them to solve puzzles.
* Adjust the beginning of second level. The puzzle is more complicated and difficult.
* Adjust the hardness of the last two parts in level 3. The puzzle will be more interesting.
* Adjust the checkpoint and camera checkpoint
* Adjust the camera moving for all levels.