I don't know who else is playing Celeste but, I must say, the dialogue is probably the best I've ever seen displayed in a text box. I think the voice effects certainly help!
https://youtu.be/_bM0uEAis14?t=4m1s
It's funny, because when I first heard the voices, I disliked them, but they IMMEDIATELY grew on me, I guess because they remind me of Towerfall
Anyway, what I really like, besides the voices and obviously delightful character animations, is the text jiggles/ waves, which change drastically later on to express a whole range of emotions, like fear and excitement. Also, minor spoilers,
when the character profiles jump out of the frame, even the UI box, I was amazed! They looked so cool and really opened my eyes to what narrative boxes can be capable of.
And it got me wondering... Can this be done in Ren'Py? I imagine the stuff mentioned in spoiler can be done with the correct animation sprites, but the jiggly/ wavy text seems like it would be a challenge I'd love to do it, because it's such an effective way to highlight text, instead of just using bold or italics.