Artifacts describe how you played each level.
For example you will get a FARSPEER artifact when you hit enemies, that are far from you.
*You can only recieve 3 artifacts at the end of a level, even though you met the requirements for more. The artifacts are ranked, so it is possible that the artifact you are going for will get burried and not come up. The devs patched this a while ago and adjusted the ranking of the artifacts but it might still happen.*
Hints for I see the Licht artifact:
When you hit an enemy that is close to you (just before it kills you) you receive a NDE (near-death experience).
You need to receive at least 3 NDE during one Level to obtain I see the Licht.
Remember that you cannot die on the stage after receiving NDE. For example, you get NDE, than you die (on the same stage) it resets. You need to finish the stage after obtaining NDE to "save" it.
I just started the first level, got all 3 on the first 3-4 enemies and then just played to the end of that level and it unlocked.
Here is a video if you want to see a few NDEs:
Good Luck!