This is pretty impressive concept for a game, with the emphasis on quiet dread, suspense, and deception coming full force with its trading and feeding game loop, grayscale watercolor aesthetic, and quiet isolated sounds somewhat startling the player. It's an experience that effectively injects a small but long-lasting fear in the player's subconscious.
Some complaints about the game are the UI for the microwave and the stand, the skewed imbalance of the first batch of items compared to the incoming trades, and the puzzling existence of the siren off button.
When starting out, it was difficult to find my first items to start with. That is until I randomly clicked buttons on the microwave, which I didn't know were interactable due to a lack of visual hovering feedback. Additionally, the stand's interactive elements are pretty unintuitive, with only the counter being the interactive element for trading while the entire window is for opening and closing it instead of just the roll-up gauge. This often made me accidentally closing the shop instead of trading, which lost me the customer.
As for early-gaming balancing, the items given by the microwave are often worth little in value, especially when constantly dealing with numerous expensive trades that needed to be exceed in value without individual selection of items to trade. If trading for all items is intended, then having lower value trades showing up more often would aid the early game.
Finally, there's the siren off button, which is the most pedantic critique I have, but still a bit baffling to have, due to the siren been the only indicator of darkness lurking around.