Adopting Slay the Spire's enemy turn indicators was a very smart decision; the game is full of great strategic moments thanks to it. However, this inventory management system is wholly unique -- I love the "adjacent" bonuses and tradeoffs: it's a different kind of 'strategy', but a nice break from battles.
I would love to see more kinds of unique item placement mechanics and interactions (like the energy-granting rings that can't touch anything, gems augmenting weapons on columns or rows, and the fish-sword that's powered up by fish) -- for example, a rat companion that will burrow into your backpack and eat your food and grow bigger the more it eats, but provide you with buffs during battle. Inventory slots could also be elementally charged; putting a regular arrow in a fire-charged slot could give it a damage boost, but burn up any wooden items placed inside.
The point is, there's a lot of good things here and so much room to expand on this concept. And I love the character designs! The merchant frog and main character are wonderfully charming.
Awesome work.