For all the endings achievements make sure to choose play the game in visual novel mode the second option and choose the special ending option the second option once again.
In order to get all (Kurt) endings in one play-through you have to choose these choices:
(You think that's all it's gonna take to impress me)
(I dunno)
(Keep confident you can help)
(Running back)
(Show him with Darren)
(Accept)
(Don't let him)
(Go along with it)
(Cookies)
(Yell at him)
After you finish picking up all these exact choices both achievements for both endings will unlock.
Hope this helps!
Also check this perfect full achievement guide done by Cheevo Guides
