I feel like Episode 4 left the biggest impact, I think, it's has a few problems, for one Max loses agency going into the vortex party, their's a bit of a disconnect here. But it still had the confrontation with Frank, the detective puzzle, the dark room reveal, resolution with most of the core characters at the vortex party, the Mr. Jefferson reveal, Rachael Ambers fate, the scenes with alt. reality Chloe. It stands out to me as both having the best and the most content, which is surprising to me.
Episode 5 I'll sit in second place for now, obviously it's build very heavily on what's come before -- but you'll see for yourself soon enough.
[Both episodes 2 & 3 sit quite equally for me, each time I look at this order I change my mind whether I like 2 or 3 better]
Episode 2 was the Kate episode, her arc may as well have began and for some of us (me included), ended in this episode as well, a really powerful,more self contained story. Kate dying at the end was something I'll never forget, I'm still upset I couldn't save her.
Episode 3 one of my favorite moments in the whole series, which was the morning after the school break in. Just lying in the bed listening to music beside Chloe, that was a really effective scene to me. Episode 3 overall was a little more underplayed and subdued than episode 2, after Kate's suicide it was appropriate to take some down time, after all. This episode built up Chloe's character the best out of all of the episodes, (maybe tied with Chloe's scenes in the alt. reality in episode 4) making her truly likable and compelling. I didn't completely warm up to her until the break in scenes. Jumping into the photos was a great thematic addition to Max's power set, too -- and the cliffhanger of Ep 3 might be the best one of all -- even better than 4 as far as intrigue goes.
Episode 1 is still fantastic, it built a great foundation, and the rest of the series capitalized on it.
I can see any order being justified though, there's no real weak episode -- I think 1 sits at the bottom, it has the least going on, but it's a strong start. 4 I think everyone can agree had the most going on, and wins purely because it got most of the big payoff scenes -- it's hard to fuck up with the opportunities and scenes episode 4 is given. 5, 3, & 2 I can see being mixed around in any order though.