Hints
Below are a maximum of 3 hits for each box, designed to hint the solver to how the mechanisms work, not give them the solution. However, I can give full solutions to those who require them by request.

Interlocked Box:
-HINT 1: Up before Out.
-HINT 2: Line up holes.
-HINT 3: Deadbolt.

"Bitesized" Box 1:
-HINT 1: The gear can only move in one direction. Why?
-HINT 2: There are two locks on the drawer.
-HINT 3: 1x2 tiles can slide.

Jewel Heist Box:
-HINT 1: Look at the small details.
-HINT 2: Differential.
-HINT 3: Use both hands.

"Bitesized" Box 2:
-HINT 1: The deadbolt is the key.
-HINT 2: The coin is loose within the box.
-HINT 3: Get away through the roof.

Black Box:
-HINT 1: Red means fail.
-HINT 2: Move upwards.
-HINT 3: 1 and 3 in, 2 out.

"Bitesized" Box 3:
-HINT 1: Red means fail.
-HINT 2: Green means success.
-HINT 3: There is not much else to it.

Spaceman Box:
-HINT 1: Backpack, arm, head.
-HINT 2: Both sliders need to be out.
-HINT 3: Gravity.

Origami Box:
-HINT 1: Axle drops.
-HINT 2: In and then out.
-HINT 3: Gravity.

"Bitesized" Box 4:
-HINT 1: Gravity.
-HINT 2: Pull not push.
-HINT 3: That's all there is to it.

Polar Box:
-HINT 1: The drawer is not success but the path to it.
-HINT 2: Feel inside and outside.
-HINT 3: Work from bottom to top.

Gift Box:
-HINT 1: Work upwards.
-HINT 2: Gravity.
-HINT 3: The box is not the final step.

"Bitesized" Box 5:
-HINT 1: The drawer is not success but the path to it.
-HINT 2: Work from bottom to top.
-Hint 3: That's all there is to it.

Vault Box:
-HINT 1: Unleash the puzzle using the lockpick.
-HINT 2: There are four boxes within the puzzle.
-HINT 3: Use the top box last.

Earth Box:
-HINT 1: Pull the right side.
-HINT 2: The handle can do more than open the drawer.
-HINT 3: Deadbolt.

Water Box:
-HINT 1: Push to release.
-HINT 2: Don't give up, there are lots of gears.
-HINT 3: The top isn't just for decoration.

Air Box:
-HINT 1: There are three sections.
-HINT 2: Work upwards.
-HINT 3: The third layer can move in more ways than one.
-RULE: NO ROTATING LAYERS.

Maroon20 Box:
-HINT 1: Linear Actuator.
-HINT 2: Backtrack.
-HINT 3: Work upwards right up to the top for treasure.

April Fool's Box:
-HINT 1: Discover all of the mechanisms.
-HINT 2: Give up or destroy it.
-HINT 3: That is all there is to it.

Fire Box:
-HINT 1: Orientation.
-HINT 2: Chaos and luck until the drawer unlocks.
-HINT 3: Give up.

Unnamed Box:
-HINT 1: Work upwards.
-HINT 2: This box features many DIFFerent mechanisms.
-HINT 3: Backtrack is key, and back and forth with the key.
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