I don't know of any guides that are completely spoiler free, but I will try my best to make one here.
The text on the actual choices has been altered to be as spoiler free as possible.
Of the five routes only Carl, Leo and Jenna have multiple endings.
Carl's branches with the choice of fight it/Let it in. Let it in leads to a Bad ending (This branch is fairly long and provides an alternate set of events from the good ending), while Fight it leads to another choice, Grab her/Push her. If you chose Grab her you get another bad ending (Albeit a fairly short one), while Push her leads to the good ending.
Leo's route branch's first at Help him/Grab gun. Choosing Help him leads to a bad ending (Ending relatively quickly after making this choice), while Grab gun leads to the next choice It's Over/Work it out. It's Over leads to the good ending, while Work it out leads to the bad ending (But I recommend checking both as it's rather short and really impactful).
There is a question in the Prolouge that determines if Jenna's Route will include a romance or not. Your options are Yes I'm gay (No Romance)/No I'm bi (Romance). Jenna's route branches with the options I don't know how to answer that/We kept each other sane/This town breaks people. The first two choices lead to the good ending, while This town breaks people leads to the bad ending. I should mention that all three choices affect some scenes later on, but there are only two endings that I know of.
If there are any other endings that I missed, I will try to add them.