I'm playing the Japanese version of Shin Chuka Taisen/The monkey king (wii) in order to write a review of it for the site "shmup.com" (which, as you all know by now, is the best French speaking shmup site you'll ever see !
) BUT after 1cc both the normal and the story mode (5 stages, no staff roll, "game over") I found out on the site "Hardcore Gaming 101" that the game has actually 6 stages (the last being Hell) and then offer to play the game backwards ! 
They even show a picture of a boss I've never seen, which then should be the 6th :Most of the levels are the same [compared to the 80's arcade version], with the addition of a totally new level which takes place in Hell. Here, you refight all of the old bosses, then take on a new final enemy. After this, you need to go through all of the stages in reverse, except you're flying from right to left. It's an interesting twist, but it's not nearly enough to save the game.
Can someone explain to my disturbed self how it comes, as I'm playing of course with the "default" options (normal difficulty, 5 lives, and I've also tried with only 3 lives...), how it comes I don't meet that 6th stage ???
Thanx for your (accurate and really kind) answers !