I haven't tested it out yet, but the creator said: "yep! Just act bored to him". I will try to get it soon, if I do get it I could give you the specific options.
I did not and gave up, but thanks to your comment I noticed that it was because I was using an old version. You should check if you have the newer one.
Here I'll leave the answers I used to get each ending.
Btw, ending 2 appears as ending 3 in-game, so I'm not sure which one you're missing.
Ending 1: (You can get different kinds of ending 1, it just changes your behaviour)
1- Insist that it's him
2- Be petty
3- Help Salem
4- You were glad to see him
5- Play along
6- Sure, I'm down for anything
7- Down the hatch
8- Got any seconds?
9- Accept
Ending 3 (?)
1- Insist that it's him
2- Do it out of spite
3- Don't help
4- It's whatever
5- Just head back
6- ...?
7- Sure, I'm down for anything
8- Down the hatch
9- That was gross
Ending 3 (?)
1- Insist that it's him
2- Be petty
3- Don't help.
4- It's whatever...
5- Just head back home
6- ...?
7- I'm not really feeling adventorous
8- Refuse.