I found a bug on Klonoa 2 Lunatea's Veil that make the game crash when you finish a level and try to return on the level select screen. I use OPL 1.0.0 in case you need to know.
Actually I managed to finish the game on OPL w/ USB about 2-3 years ago, the only problem with this method is the last credits FMV will only play for a second then it skips straight back to main menu.