I forgot Serous Sam. It definitely has a humorous side. I remember finding a secret area and expecting extra loot, but instead I got "You discovered a secret ambush!" and enemies spawned all over. The titles you mention give me some hope that a parody would be well received enough to be worth the effort.
The sceenshots for Hourai High School look like just the type of humor I appreciate: subtle, but consistently present and not relying on cheap 'fart joke' type gags. I am definitely going to give it a play. I'd actually love to translate a funny game like that, but I strongly suspect my Japanese skills are not up to the task. I routinely run into phrases I'm not familiar with and have to rely on research to sort them out. With something as subtle as humor, I'd probably be like Edward Scissorhands trying to pet a puppy.
Anyways, thanks for giving me some feedback. Hearing what other people think always helps me crystallize my own thoughts.