All possible passwords:
lewdbruteloader (loads all lewd scenes, changes to next one when you press the "x" button)
formbruteloader (loads all forms)
horudevmode (unlocks everything)
horusynergies (shows a list of all combinations)
apparently anything that begins with "s:" (too lazy to figure it out, but you can input the cup, form and previous cup and it shows you the code for it or something, not too interesting)
horuwords (shows a list of all words)
debug/test/dev (easter egg)
horu/horubrain (easter egg)
To put in these codes you have to go to the main menu and press on the cup the girl is holding.