The "Tutorial" is a shooting gallery, not a tutorial. It does need one because the mechanics/UI aren't explained anywhere.
The "Sair" button makes the screen black but the music is still playing. Why is there an Exit button on a Browser game?
There's not enough content here to comment on yet, sorry. The movement is a little sluggish and the Golden Gun is OP but I would prefer waiting until more is added to "review".