Been saving this one for a rainy day because DAMN that art. I have a soft spot for sketchy styles. And different fusion arts for each of the selectable characters is cool, the cat's my favorite one. The world presented is interesting and unique.
However, I feel like the combat is a little bit of a mess. A lot of turns feel wasted because of the enemies super high defense, especially since dealing 0 damage leads to no direct visual feedback, just the turn ends popup. And I can't imagine how any perk but Independent has any use given the high defense numbers.
The combo mechanic is just pure RNG, not something you can properly setup or plan for. It's completely passive and easily forgettable aside from "Oh, I have a 3 combo, guess I can oneshot an enemy now".
In more minor issues, it's not immediately clear which enemy is which on the field, sure stuff like "Titrex" is fairly obvious, but only having the names deciding targeting isn't really clear enough. Though I'm not sure how much is even possible within renpy as an engine.
Bug: Having a party member dying then reviving due to regen doesn't actually properly revive them, they don't get turns despite going back to their full form visually
The combat will be immediately more engaging once a 3rd party member is added and you'll get the additional option of deciding who to fuse with to immediately increase the strategy of battles. I do hope to see continued development despite how harsh my comment may come off. I see a lot of potential in this concept.