It's actually impossible to reach 100% completion on game achievment, I"m guessing it's cause the loyalty/helicopter achievments aren't in the game but since they're not they shouldn't count towards it right now
Here's a picture, right now it shows up with me having 33 more achievments to do but the only achievments I have left available are the 600hour/1200hours/2400hours ones
Also I'm not 100% sure but I think the raid achievments are bugged as well, missing the 100 runs achievements for each raids 'clear last carnival 100 times' 'clear junk hive 100 times" "clear bandit highway 100 times' 'clear iron castle 100 times'
