Time limit is 35 steps (not seconds). All gems needed. Rocks cannot be snapped. The postcard says something like "if you got this envelope but didn't snap, you might need to rethink your plan"
BONUS: The level can be solved with the starting step count set to 33.
SUPER RIDICULOUS: The level can still be solved if any one of the fuel containers is replaced by a spent fuel container, or a rock. (If the bottom left fuel is the one that becomes the rock, you can even make both the rock-replacement and 33-step adjustments and still have a solvable level.)
To be fair, pulling off the 33/rock combo absolutely requires a frame-accurate maneuver: snapping a falling gem in midair. Without that, you can still complete the level with a rock in that one particular spot, but you'd need all 35 steps.