1. Use Penis item and choose to masturbate
2. Use Vagina item and masturbate
3. Use Dildo
4. Use Fleshlight/Onahole
5. At the door on first floor, use Penis (safe option - use Dildo)
6. 2nd floor, walk through the dark without using candle (safe option - use candle, duh)
7. 3rd floor, after finding the penis on the wall (from the maze, keep going left) use Vagina (safe option - use Onahole)
8. On the 4th floor, enter the room with no enemy, then keep walking inside (safe option - use Earplug after you get the first message)
9. 5th floor, fireball the slime and let it catch you (safe route - run back and open the floor to drop it down)
10. 6th floor, go past the plate that warn of danger ahead (safe route, in the same room with said plate, there's a small hole near left entrance, investigate and go through it)
11. 7th floor, walk in the water (safe route, hop on the lilypad until you cross)
12. 8th floor, sit on the chair (safe route - on the previous floor there's a chest with empty bottle, use that to store water where #11 was)
13. 9th floor, fail the jumping puzzle (safe route - don't fail it .- .)
14. 10th floor, fall into the hole (safe route - jump over it)
15. 11th floor, walk on the plant (safe route - find music box of winter and use it, it'll turn the plant brown)
16. Runs out of MP (well, technically you drop to 9mp, but since your fireball cost 10 to cast you're effectively out)
17-18 Have low max MP when you finish the tentacle fight at the end (not sure how low, I dropped to 49 MP just to be absolutely sure)
19-20 Have a fairly high max MP when finish the fight, but not too high (I had 459, which I get a feeling is right at the threshold)
You get no CG for clearing with 'virgin run', but there's a scene of it in the gallery.
The 4 endings (if we count the bad end) are basically
0MP - Litis become tentacle birthing slut.
Low MP - Litis got out and become owner of El (the staff spirit), but she remain a futa and is constantly horny that eventually El sorta turn the table by making Litis agree to become her slave instead of the other way.
Decent MP - Litis got out and the two travel together, she is still a futa in this one as well, and is still easily erect. But unlike the low MP end, the two pretty much ends up addict to sex with each other .- . which means by far this is the 'happiest' end.
High/max MP end - Litis seem to have El fix her body back to normal, this end is just the two talking about where to go next (El suggest a place where another one of her old buddies currently resides in, which Litis declines), pretty much Litis being a killjoy and keeping El in check in this one '. '