In fact, the title of every level is a hint for the solution (sorry for no English version). The 4th level's title is basically a character by character reversed version of "Sokoban".
So in this level, you can pull the box instead of pushing it.
Viewing post in Yet Another Sokoban Game? comments
You can use the level select [esc] to skip.
Machine translated titles - I'm sure its missing some jokes etc.
| 1 | 第一关 | First level |
| 2 | 换位思考 | Put yourself in someone else's shoes |
| 3 | 贴图混乱 | Texture Chaos |
| 4 | 子箱推 | bankoso |
| 5 | 换位思考2 | Put yourself in someone else's shoes 2 |
| 6 | Wall is Duck | |
| 7 | 换个参考系 | Change the reference frame |
| 8 | 黄昏 | Dusk |
| 9 | 是鼠标鸭 | It's a mouse duck |
| 10 | 啊? | Huh? |
| 11 | 有尝试过跳跃吗 | Have you ever tried jumping? |
| 12 | 似乎与数学有关 | Seems to be related to mathematics |
| 13 | 重力 | Gravity |
| 14 | 你不要过来啊 | Don't come over here! |
| 15 | CraftMine | |
| 16 | 屎不拉通 | Constipated (?, probably wordplay) |
| 17 | 自由! | Freedom! |