ENDING: A True Gentleman

The easiest to get ending. Just don't be overly nice to Sophie (e.g. don't offer to cook for her, etc.), and go straight to bed on the night of day 3 (i.e. when prompted with "Caress her gently" or "Go to bed", you choose "Go to bed")

ENDING: As Dead as a Rapist

Be an ass to Sophie throughout (don't offer to cook for her, don't go on a walk with her, don't tell her her top has come undone, etc.). On the night of day 3, do not go to sleep and choose "Caress her gently", "Touch her breasts", "Cross it", and finally "Go on."

ENDING: Dead Date Drug Rapist

Don't cook for Sophie (and don't joke about touching her boobs either). When prompted, say "She's a bitch". When Sophie asks what you thought about her food, choose "Tell her she should have used the spices." When given the option, after seeing Sophie's boobs, to go out into the jungle, choose "Don't overextend yourself." Hypnotic means sleep-inducing. When given the option to masturbate, take it. When Sophie accidentally interrupts you, choose "She shouldn't sneak up on me like that." Go into the jungle. Moss grows on the north side of the trees, and you live on the western side of the island. When you see the herb, take it. When you're cooking, use it on Sophie's food.

When Sophie's asleep, do not go to sleep and choose "Caress her gently", "Touch her breasts", "Cross it", and finally "Go on."

ENDING: Rapist

Offer to cook for Sophie. Don't go on a walk. Tell Sophie her bikini has come undone. Don't overextend yourself. Leave the snakebite as it is. Go fishing. Take the leftover roots for yourself.

On the night of Day 3, do not go to sleep and choose "Caress her gently", "Touch her breasts", "Cross it", and finally "Go on."

ENDING: Regrets

Offer to cook for Sophie. Go for a walk together after dinner. Ask her what she misses the most. When she asks you, say you also miss food the most. When Sophie's top gets undone, tell her. Choose to head into the forest afterwards. After Sophie's been bitten by a snake, don't choose to stay with her. When you get back, let Sophie have the few roots you had left over.

On the night of Day 3, choose "Go to sleep" or "Try and go back to sleep".

ENDING: Nothing to Tell

Same as for "Regrets", but on the night of Day 3, do not go to sleep and choose "Caress her gently", "Touch her breasts", "Cross it", and finally "Go on."

ENDING: Paradise (True Ending)

Exactly the same as for "Regrets", except for when taking a walk on day 1, ask Sophie if she wants go to back.

The cheats in the game are, as follows (type this in on the main menu screen):
"iloveboobies" - No Bra
"odysseyofthelostbikinibottom" - No Panties
"nudetella" - Completely Nude
"destined" - Play as Sophie's brother instead of her cousin
"shavednotstirred" - No pubic hair on Sophie
"oldschoolcheat - Unlock all CG illustrations in the gallery
"papabear" - Play as Sophie's dad instead of her cousin
"notsoclose" - Play as Sophie's close friend, instead of her cousin
"kittykitty" - Turn Sophie into a catgirl with a fluffy tail
"fluffykitty" - Turn Sophie into a catgirl with a foxtail (or Dog tail?)
"legolasbride" - Sophie and the nameless protagonist are turned into elves living in a modern version of Middle-earth.
"receptacleforthebespectacled" - Gives Sophie glasses