Why is everybody bashing this?
He is offering to pay money for building game-assets, right?
That's a chance to actually work under close-to-industry-conditions and it get's you an extra buck or two.
Who cares, if the genre is overused? Who cares if it ends up unfinished?
Unless you start your own company with your own funding, you will always have to submit to other's directions.
Epic won't sign a hobby-developer with zero industry-experience, trying to tell them how to do their job properly...
If your portfolio is about photorealistic game-assets and lacks WW2 stuff, go for it.
If not just go outside and take a walk!
If I was able to deliver the desired quality, I'd give it a try.
I'd do assets for Tomb Raider 27, if it was worth the payment.
Sheesh!