The mechanic of being able to switch characters that you control is something you don't see very often, if ever, in point-n-click games. It was nice to see it incorporated, but I got the feeling that it didn't end up adding very much depth to the game because the puzzles were still fairly straightforward without much brain-busting over how to keep multiple characters coordinating to achieve a goal. If you decide to make a sequel, I would definitely recommend putting a good deal of work into designing puzzles that exploit that mechanic well -- and if you can really get people to have to think outside of the box to use character switching and cooperation effectively without it becoming tedious to manage then you'll have a real gem on your hands.
A less important point but one worth mentioning is that the controls seemed a little clunkier than with most point-n-click games. I'm not sure how your game engine is set up and whether it would be easy to change, but maybe it would be easier on the players if the arrow by default becomes either a walking symbol if the mouse is over a walkable area and you move there if you click, or a magnifying glass if it's over an interactable object and you look at an object if you click, and there are buttons at the bottom for interaction and talking etc that would override the walking or looking actions if you select it. And for the inventory: pick stuff up by using the interact button on the object to pick it up without having to use a separate inventory button, always have the inventory slots up so you can click on any object in your inventory to try to use it, and get rid of the current backpack-shaped inventory button entirely. Or just find a point-n-click game you like a lot and see how they handle user interface stuff and do something similar.