what's the secret medal? i was thinking it had something to do with clearing the game quickly but i got flawless in 214 seconds and that wasn't it.
not sure if i can do much better than that
edit: as a matter of fact, i did realize you could trigger the serpent and the raven at the same time, but i simply assumed it was a bug, not a feature.
i managed to softlock myself: if you trigger the raven, you can trigger the serpent during the raven fight because it's close to the fighting area.
if you defeat the raven and then die, the game saves in a state with the sky serpent triggered, and if you die it will continuously kill you as it circles around your respawn point.
edit 2: turns out the serpent can be triggered with either of the other two, because it doesn't have an area delimiter like the other two.
if you trigger the old one, you can get it to punch the serpent in the face, which is much faster than defeating it normally. might try for a faster time knowing that
edit 3: with sky serpent skip and no deaths, cleared in 74 seconds.
as a side note, if you defeat the sky serpent with the skip and the old one, without dying, and then you fight the raven, the camera stays zoomed in and locked in the location where you triggered the fight (camera doesn't zoom out, and stops following the player character. the fight works as normal).
dying during the fight prevents this from happening (dying to the old one after defeating the serpent) or fixes it (dying during the raven fight makes the camera for the subsequent fights work as normal); dying before the double boss fight is irrelevant in regards to the bug.
tl;dr defeating serpent and old one at the same time without dying (during the fight) causes a bug with the camera if you leave the raven fight for last