I must admit that inertia is a bug caused by the dash...
In the updated version I already added iframes, but during the jam I didn't know how...
And of course there's a lot I'm fixing for next week, like:
death menu,
functional options,
bugged reflections,
secondary weapon selection (I made 3 secondary weapons but didn't know how to implement data persistence and it ended up not going to the jam),
the boss itself (in some tests the weapons would detach from the body)...