Here is the full list of all 42 Langrisser I & II achievements.
Cleared Chapter 12, Route C in Langrisser I without defeating Sar Galious.
Cleared Chapter 11, Route A in Langrisser I without defeating Lance when he appears.
Cleared Chapter 1 of Langrisser I.
Acquired all Langrisser I & II achievements.
Cleared Route A in Langrisser I.
Cleared Route A in Langrisser II.
Cleared Route B in Langrisser I.
Cleared Route C in Langrisser I.
Cleared Route D in Langrisser I.
Cleared Route E in Langrisser I.
Cleared Route F in Langrisser I.
Cleared Route G in Langrisser I.
Cleared Route H in Langrisser I.
Cleared Route B in Langrisser II.
Cleared Route C in Langrisser II.
Cleared Route D in Langrisser II.
Cleared Route E in Langrisser II.
Cleared Route F in Langrisser II.
Cleared Route G in Langrisser II.
Cleared Route H in Langrisser II.
Cleared Route I in Langrisser II.
Cleared Route J in Langrisser II.
Cleared Route K in Langrisser II.
Cleared Route L in Langrisser II.
Cleared Route M in Langrisser II.
Cleared Chapter 17, Route A in Langrisser I without Chris being defeated.
Cleared Chapter 16, Route C in Langrisser I without Lance being defeated.
Cleared Chapter 14, Route E in Langrisser I after failing to save Betty.
Cleared Chapter 17, Route E in Langrisser I after defeating Chris.
Cleared Chapter 16, Route G in Langrisser I after making Jessica an ally.
Unlocked all classes for Ledin.
Cleared Chapter 1 of Langrisser II.
Accepted Leon's proposal in Chapter 7, Route A in Langrisser II.
Declined Leon's proposal in Chapter 7, Route A in Langrisser II.
Acquired Langrisser in Chapter 11, Route A or Chapter 11, Route G in Langrisser II.
Defeated Boser in Chapter 13, Route A in Langrisser II.
Defeated Bernhardt in Chapter 13, Route A in Langrisser II.
Succeeded in the final persuasion of Sonya in Chapter 17, Route G or Chapter 20, Route I in Langrisser II.
Succeeded in persuading Laird in Chapter 20, Route E in Langrisser II.
Surrendered Langrisser to the empire in Chapter 11, Route G in Langrisser II.
Allied with Boser in Chapter 16, Route K in Langrisser II.
Unlocked all classes for Elwin.