In a lot of runs I see the player turning the pod sideways very frequently. It's not a strategy that I ever considered before. What all does it accomplish in a speedrun?

it just makes your hitbox more narror so you can maneuver between obstacles more easily without touching anything. Usually gets used while boosting, so you avoid hitting things and getting the boost cancelled

It's also very helpful to avoid a lot of the random floor deaths the game throws at you

https://www.speedrun.com/swe1r/guide/fsqjp