Here is the full list of all 50 The Chronicles of Narnia: Prince Caspian achievements worth 1,000 gamerscore.
Fend off the Telmarine ships.
Rescue Queen Susan's Horn from the throne room.
Defeat the archers that are threatening Cair Paravel.
Seal the doors and escape Cair Paravel.
Escape Cair Paravel with Queen Susan's Horn.
Use the giants to destroy the catapults in Cair Paravel.
Work through the cavern to find a grapple.
Explore the treasure rooms and find the Pevensie's clothes and gifts.
Rescue Trumpkin from the water.
Find a safe route through the woods.
Complete the entire Cair Paravel Ruins area.
Use gryphons to take out the turret sentries.
Defeat the sentries along the castle walls.
Rescue Cornelius from the dungeons of Miraz's Castle.
Rescue Edmund and Trumpkin from the bell tower.
Complete all of the areas within Miraz's Castle Infiltration.
Reach the control room to let the Narnian army in.
Open the portcullis and let the Narnian army in.
Battle through the courtyard to get to Peter.
Reach King Miraz by scaling the castle terraces.
Rescue Cornelius from the stables in Miraz's Castle.
Complete all of the areas in Miraz Castle Assault.
Complete the Approach to Aslan's How area.
Help Lucy escape on horseback from the How.
Defeat the White Witch.
Defeat King Miraz in the combat ring.
Successfully complete all areas in and around Aslan's How.
Defeat Lord Gregoire in battle.
Find a way into the secret cistern in Aslan's How.
Collapse the battlefield by destroying the support pillars.
Defeat Lord Glozelle in the Cistern.
Rescue Prince Caspian on the battlefield of Beruna.
Take control of the trees and destroy the Telmarine army.
Rid Narnia of the Telmarines
Open 10 bonus chests in single or co-op play.
Open 25 bonus chests in single or co-op play.
Open 50 bonus chests in single or co-op play.
Open 75 bonus chests in single or co-op play.
Open ALL bonus chests in single or co-op play.
Upgrade your health fully in the game.
Play 5 missions in co-op play.
Play 15 missions in co-op play.
Seek vengeance from 200 Telmarine soldiers.
Defeat 75 Telmarines as Susan.
Defeat 25 enemies as Reepicheep.
Defeat 50 Telmarines as Trumpkin.
Defeat 20 enemies while on horseback.
Charge around as the centaur and take out 40 Telmarines.
Issue a reply to 100 Telmarine enemies in the battle.
Send 10 guards to sleep with Cornelius' sleep potions.