Here is the full list of all 17 Legion 51 achievements.
"He wanted his death to be like his life. Don’t let him die in vain." - Make your first attempt.
“Greatness awaits.” - Reach 25 fans in your Legion
“I can’t fit any more people!” - Fill the whole field with your fans
“A little bit of everything.” - Attain 3 Tier2 fans of each type
“Jump on the hype train!” - Collect 5000 hype points
“You’ve done the easier half.” - Reach the third outpost
“Illuminati confirmed.” - Enter area 51
“Why do you persist, Mr. Fandreson?” - You tried 51 times
“Do you have any idea of how fast I am?” - Triple your running speed with stayers
“One man does not make a legion, but one fan does.” - Reach an outpost with only 1 fan left.
“What a shame huh? Yet almost doesn’t count.” - Your legion got wiped barely reaching an outpost.
“Quantity does not equal quality.” - You had a full legion and dies nevertheless.
“You achieved immortality… well, kinda.” - Have enough chemists to get 300 hp bonus.
“Boom! Fifty men gone in an instance.” - You lost 50 fans in less than 5 seconds.
“You just can’t seem to get enough of it, huh?” - Finish the game for the second time.
“I’m the fastest man alive.” - Finish the game in 12 minutes.
“It’s a collector’s edition *wink*.” - Pick up 200 hype points in one run.