No. Just no.
This concept art is definitely wrong direction. It is funny, but it will ruin the mood.
This game needs a "CONTRA" feeling - not the "Drawn Together".
So, my opinion - this is appropriate only as few-time completion unlockable bonus, as a joke, along with some serious ones.
And serious skins should be inspired by sci-fi movies of 80's but with more "soviet feel". Some military-cyborg-supersoldier stuff. Robot or Mutant will be fine too!
Even cyborg with the crocodile head, with the name "Gennady" will be ok. But not the Mummy, Gorilla, and some crossdresser in japanese school uniform.
I do REALLY like your project and i don't want it to go wrong.
So - this is my opinion.
PS: Good luck to all of your team!