Hello folks. Below is a text version of the solution as well as a timestamped video for all 5 Achievements in Title Update 3.
For Secret Crystal 2, we need to play Level 6. Levels unlock as you play the game, so you'll need to get through the previous levels to get here.
When you spawn in, you'll notice the crystal to your Northwest across a two-space gap. Luckily, you're surrounded by boxes. Push the one above you up to the wall and left twice, then push the right-most block up twice and left four times, then walk across to grab Secret Crystal 2.
Level 6 starts at 1:57