Young Justice Legacy

For this achievement, you need to collect 14/28 total dioramas. The times in parenthesis next to the costume indicates where in the video it can be found if you prefer a visual guide. The first 14 dioramas are as follows:

GREECE

MISSION 01 / ARRIVAL / RUINS
Cheshire Diorama – (0m01) - When you get to the fork in the path, break all the pots to your left and it’s right in the middle of the ruins at the top of the stairs.

MISSION 01 / ARRIVAL / DIG SITE
Sportsmaster Diorama – (0m35) - Shortly after you continue on the path up from the scaffolding, you’ll see loose looking rocks in between two wooden beams on the left. Break this wall down to discover a secret area with the diorama.

Cheshire Diorama – (0m58) - Once you reach the big open area with the temple, walk up the wooden walkway on the right all the way to a dead end with loose rocks. Destroy this wall to discover another secret area and progress forward to the diorama which is on the highest of three pillars by the waterfall.

MISSION 02 / A HOSTAGE CRISIS / MUSEUM
Sportsmaster Diorama – (1m38) - When you first enter the museum and take care of the first group of enemies, head up the stairs on the right and follow the railing around to the right till the end.

SIBERIA

MISSION 04 / COLD CHASE / SIBERIAN ICE PATH
Lex Luthor Diorama – (0m30) - Right after the sharp right turn, you’ll see two little divots on the right side. Destroy the ice wall on the second divot you come to and you’ll discover the Diorama and a secret area.

Killer Frost Diorama – (0m50) - Just keep following the path and on the last straight away you’ll see the diorama on a box to your right.

MISSION 04 / COLD CHASE / ICE RIVER
Icicle Jr. Diorama – (1m25) - After you cross over the gap for the fourth time (two boat sections after the missiles start raining down on you) you’ll see this diorama up on the boxes on the top of the screen.

MISSION 04 / COLD CHASE / BASE CAMP
Lex Luthor Diorama – (1m38) – after you reach the fourth villager you need to save located in the top middle of the map, there’s a fenced in area to your right when looking at the villager from where you came. Break through the fence and jump on the boxes to the diorama.

Killer Frost Diorama – (2m00) – When you walk into the next open area with the frozen villagers, jump up on the truck straight and to the right and then look left when on top of the building.

MISSION 05 / DEEP BURIED IN ICE / MOUNTAIN TUNNELS
Icicle Jr. Diorama – (2m23) – After you leave the room with the first group of enemies, look to your left for a strange wall before the path turns right. Destroy this wall and you’ll find the diorama on top of some boxes at the end.

MISSION 06 / GO WITH THE FLOW / FLOODING TUNNELS
Lex Luthor Diorama – (3m39) – In the first room it’s on some boxes on the left.

SANTA PRISCA

MISSION 07 / JUNGLE RENDEZVOUS / SANTA PRISCA’S JUNGLE
Bane Diorama – (0m01) – After the cut-scene at the first rendezvous point with Aquaman, you’ll reach an area with two trucks/cars. Jump on the one on the right and onto the boxes to reach the diorama.

Black Manta Diorama – (1m19) – at the last bend of the map, right before the final objective, walk around the corner on the left to see the diorama sitting on some small stairs.

MISSION 07 / JUNGLE RENDEZVOUS / HANGING STATUES OF SANTA PRISCA
Bane Diorama – (1m41) – When you cross the long bridge and can go either right or left, go right. At the end to the left is a raised gold face/statue that has the diorama at the top.

Below are the video guides credit to Redemption Gaming

Edit: Had to change video links and update time stamps