Here is the full list of all 25 A-Men achievements.
Exterminate 5000 enemies.
Complete all missions in the Forest, at the Seacoast, in the Winterland and in the Factory with S rank.
Complete all missions in the Factory with S rank.
Complete all missions in the Forest, at the Seacoast, in the Winterland and in the Factory with at least A rank.
Complete all missions in the Factory with at least A rank.
Complete all missions in the Forest, at the Seacoast, in the Winterland and in the Factory with at least B rank.
Beat the final level in the Factory.
Read all tips in the Forest, at the Seacoast, in the Winterland and in the Factory.
Complete all missions at the Seacoast with S rank.
Complete all missions in the Seacoast with at least A rank.
Exterminate 1000 enemies.
Buy all shop items in the game.
Buy 10 Commando shop items.
Buy 10 Muscleman shop items.
Complete all missions in the Winterland with S rank.
Complete all missions in the Winterland with at least A rank.
Unlock the first Winterland level.
Unlock the first Seacoast level.
Buy 10 Spy shop items.
Complete all missions in the Forest with S rank.
Complete all missions in the Forest with at least A rank.
Unlock the first Factory level.
Kill 10 enemies in the combo 10 times.
Buy 10 Engineer shop items.
Buy 10 Private shop items.