I didn't playtest it enough to smooth out the balancing but am just blindly hoping that it's at just the right amount of challenge, lolz. (This is why difficulty modes are invented)
It's actually yellow (Pleasure) that Yuyuko wants, and you get to keep all of it instead of /giving/ it away :P Collecting enough would just unlock some new dialogue from her plus she gives you free phantoms to pad that number.
Hm, the invincibility indicator didn't immediately strike me as something that can be improved upon, though suggestions are welcome!
Thanks for playing~