I like the combat visuals. The character designs are also pretty nice.
However, I think the theme interpretation is a bit weak. It only connects to the jam theme on a visual, sort of superfluous level. Would have loved to see some mechanics stemming from the "fusion" of characters.
The parry mechanics also feel a little bit off. I don't mind parrying mechanics at all in game, but I feel like either the timing or the hitboxes for melee attacks differ from projectile attacks so it feels a bit harder to parry melee.
You also said it's a metroidvania game but as far as I can tell I couldn't explore much yet. Maybe I missed something but if exploration was part of the mechanics I think it should be made clearer.
Would have loved to see more background arts and itch page visuals.