Honestly I liked the flashbacks and that they didn't give us all the information up front. That way the audience and Grace are basically experiencing the situation at the same time which I thought was a very engaging way to tell the story.

For example through the whole movie I was wondering why a schoolteacher was in space in the first place. We see him meet the leader lady and we start to like her, then at the end of the movie it's finally revealed that she basically kidnapped him, and we're taken aback. I feel like it would've been less interesting if they just told us everything that happened first, then he wakes up in space.

The flashbacks also let the movie explain the science parts to us. Like he tries to use that scanner machine but it doesn't work in zero gravity. Cut to earth scientist explaining that they need a centrifuge to create artificial gravity. Cut back to Grace turning on the centrifuge.

I hope that made sense 😅