When I finished my final regular mode in Bejeweled (Endless), the achievement for Multimode popped up, but not the one for Endless. I'm in the process of rebeating Endless Mode (on level 225 right now) to try and get it to unlock. Apparently, there are some other people who had the same sort of thing happen - the achievement for their final mode didn't unlock, just Multimode. Did you have this problem? If so, does beating the mode a second time unlock the missing achievement?