Just played for a little while to see what's up.
New standard seal of no mana regen threw me for a loop at some points. Primarily due to accidently wasting mana with the wrong jump type was a bit annoying. Though like you said in the devlog it got me to pay more attention to blue crates and it was fairly manageable.
New sprint-in-air physics are interesting. In a lot of ways it didn't feel that different to use, but in others it's a real life saver, especially when you don't have excess mana to extend the distance of a jump. It also allows for more air control in general, so it's pretty nice say if I jump a little short for the mushroom in the goop.
Water heart room is pretty neat, very vertical.