Here is the full list of all 18 Acorns Above: A World Gone Nuts achievements.
A perfect run of W.H.A.T?! No lives lost, all objectives achieved, max level.
A perfect run of Battle Blimps. No lives lost, all objectives achieved, max level.
A perfect run of Lunar Lunacy! No lives lost, all objectives achieved, max level.
A perfect run of Dam! No lives lost, all objectives achieved, max level.
A perfect run of S.O.S! No lives lost, all objectives achieved, max level.
A perfect run of Acorns Above! No lives lost, all objectives achieved, max level.
A perfect run of Dive! Dive! No lives lost, all objectives achieved, max level.
A perfect run of Sub Searching. No lives lost, all objectives achieved, max level.
Completed episode one.
Completed episode three.
A perfect run of Beta Blocker Fort. No lives lost, all objectives achieved, max level.
A perfect run of Special Delivery. No lives lost, all objectives achieved, max level.
Completed episode two.
A perfect run of Rocky's Fort. No lives lost, all objectives achieved, max level.
A perfect run of Saving Private Rodent! No lives lost, all objectives achieved, max level.
A perfect run of The Walrus. No lives lost, all objectives achieved, max level.
A perfect run of Stoned in Space! No lives lost, all objectives achieved, max level.
A perfect run of Rail Raiders! No lives lost, all objectives achieved, max level.