Here is the full list of all 43 Knack 2 trophies - there are 27 bronze, 12 silver, 3 gold and 1 platinum.
Acquired all trophies.
Acquired 70 Knack medals.
Cleared all chapters on the Normal difficulty level or higher.
Cleared all chapters on the Hard difficulty level or higher.
Acquired 50 Knack medals.
Learned all basic power-up skills.
Achieved 5 stars in every Time Attack.
Achieved 5 stars in every Coliseum Attack.
Cleared a Time Attack stage.
Cleared a Coliseum Attack stage.
Equipped a combo meter and landed a 100-hit combo.
Unlocked your first Crystal Knack.
Cleared all chapters on the Easy difficulty level or higher.
Defeated the last boss.
Defeated all Titans.
Defeated 700 robot enemies.
Learned all super moves.
Acquired all gadgets.
Learned the Ultimate Move from Ava.
Broke the blocks of 50 enemies.
Defeated the relic monster that Xander created.
Defeated Gundahar.
Defeated 50 immobilized enemies.
Learned the Boomerang from Ava.
Defeated 10 enemies as small Knack.
Defeated Rothari.
Defeated 500 goblin enemies.
Ran 26.2 miles.
Defeated 300 enemies using kicks.
Defeated 50 enemies using parries.
Defeated 100 enemies using Jump Kicks.
Stunned enemies 50 times with sunstone bombs.
Defeated 300 enemies using punches.
Learned the Hook Shot from Ava.
Found 30 chests containing relic energy.
Cleared one chapter on the Very Hard difficulty level.
Acquired your first crystal relic.
Found 10 treasure chests.
Learned the Heavy Punch from Ava.
Completed your first gadget.
Acquired your first Knack medal.
Performed your first Knack upgrade.
Acquired your first gadget part.