I don't know how much of the bar it drops but it just isn't worth it. This includes the time is took me to do all of the other game modes prior to endless, and me losing my save data twice (both at around level 100). * My total game time at the point of popping this achievement was 250h 3m. I've also heard that the 'finity mode' unlock can be glitched (it didn't happen to me) and for this reason it's very important to take a backup near to the end of the last level. However, you CAN backup your data to a pc using a usb image tool, and I highly recommend doing so regularly. You cannot 'copy' the save data for Bejeweled 2 so it's not as simple as backing up to a usb stick. * Probably most importantly, NOT QUITTING OUT OF THE GAME PROPERLY WILL CAUSE YOUR SAVE DATA TO BE LOST! It doesn't matter how often you save, if you don't quit out properly it's all gone. My total score on getting this achievement was 60,144,650, so you can calculate a percentage based on this score to give you an idea of your progress. * Each level takes longer than the one before it, so level 140 is not even close to being half way. The achievement pops when you hit level 281.
Some little things I've discovered in the hope they will help you tackle this monster: * Unlike other game modes you do actually have to complete 280 levels. It's a simple achievement but a very very long one. It's fairly obvious that the achievement itself is simple - you can't die and need to complete 280 levels. I decided to write a 'solution' for this as I finally got the achievement today.