Thanks for all the comments guys !
@Radnap Well, sorry, but I didn't have time to talk about Box2DLights in my devlog ! The Box2DLights implementation was done only a few hours before the jam deadline, and after finishing my game, I just submitted it.... and slept ! haha
@CiderPunk and @mmachida Hahaha ! Yeah the game the difficulty of my game is definitely not balanced. I lacked time to test and balance the game. The level 6 is frustrating, but it's nothing compared to the level 7 hahaha ! Actually, I am stuck to this level. If you are pissed and want to try levels 7 and 8, just open the Cosmonaut.Data file with the notepad and change the level to "8" ! The Cosmonaut.Data file is located at C:\Users\username\.prefs.