That's not how the law works. It's not a thing where this company sued another company for patents and won, therefore all future lawsuits on patents automatically win. There may be some precedent about specific details in the case, but there's no reason to assume a future judge in a future case wouldn't rule in the same way even if this case never existed. Seems to me precedence paranoia is just some internet lawyer thing.
The strangest thing about this case is that Nintendo didn't sue for trademark infringement or copyright. I assume Pikachu is trademarked and this company had a Pikachu with a machine gun on the cover of their game. Looks like an easy win for trademark infringement, given everyone referred to it as Pokeman with guns.