Haaaaaaa sehr gut!

Awesome

Hmm, I think that is not a ppsh-41, but a Suomi KP/-31, so I removed the ppsh-41, tag.

Baneslave is right.
The reply from the artist to a comment in Pixiv:

Oops! I drew it as KP/31, but PPSh may have been better.

So, the artist got it accidentally right. (KP/31 is Finnish submachinegun which Soviets later copied into their own PPSH-41)

That's the airforce roundel, not the symbol for the armed forces in general. The Finnish swastika roundel was used since the early 1920's, and didn't have to do with nazis except in a "Kevin Bacon number" sense.