I wanted to complete the game and it crashed just while defeating the final boss... But whatever, there is Mission Mode. So I chose "Final Mission", but it started Mission 1 instead. The text said "Final Mission" and I even got the Achievement, but it was just the first one.

Just in case, any developer reads this :)

I'm having the exact same problem. I probably should've listened to that French review, as it's a little disappointing to not be able to finish or continue properly. Hope someone knows a fix, or a higher up notices this.

(Should probably mention this problem is for Metal Slug X)

Edit: both bugs now fixed after the update, at least for me!