You sure those pikemen aren't Holy Roman Imperial Infantry (Austria-Hungary)? I don't think the Germans ever had a leibfahne like that... However, from my understanding, this is called "bit-art/pixel-art." I've seen quite a bit, and a couple of friends of mine do it.
1. Austria-Hungary wasn't formed untill 1860's, nearly 200 years after the Thirty Years war
2. Germany at that time (1630's) was basically a group of semi-indepedent states under the Holy roman Emperor (That was usually an Austrian, because of the corrupt succesion). Which makes Germans, Holy Roman Citizens. I can go on about the Thirty Years wars and the state of the various States under the HRE at that time, but that will take a long while. So basically, those pixel-art soldiers are Germans, they are loyal to the HRE and they are being charged by Swedish cavalry. Oh and that standard is actually the HR Standard.
Okay I'm done with my historical correction