so the achievements

[noodle96]

before the achievements came i absolutely 100% this game..
do i really have to start again to get them all?

[Rellik66]

Pretty much. The only one that showed up when I started my 100% character was the "They should totally sell those" for having all the merit badges

You could probably do just Meat Circus over to collect the figment/bags/vault achievements and get level 101(make sure you finish the punching mini-game in basic braining first,) and then play again with a new character up to meat circus without worrying about collecting every figment/bag/memory vault.