Didn't really see anyone compile videos for all of the levels done with all gems, so me and a friend decided to go through and record them. Included are all crystals (from enemies and hidden ones) as well as some safe strats for the more annoying ones to get. It's okay to die as long as you hadn't killed an enemy just prior to dying! Because of this, there are some riskier methods used but are done so in order to make it easier to collect the crystals safely with less potential to die while collecting. Hope it helps!

Timestamps also included in video description:


Level 1 - 0:00
Level 2 - 3:02
Level 3 - 6:41
Level 4 - 12:10
Level 5 - 19:20
Level 6 - 27:27
Level 7 - 36:34
Level 8 - 40:56
Level 9 - 56:06
Level 10 - 1:07:12
Level 11 - 1:15:59
Level 12 - 1:29:23
Level 13 - 1:36:25
Level 14 - 1:45:02
Level 15 - 1:59:05
Ending - 2:02:18