I tried again with right-clicking on items and then on everything else I could think to try. I eventually tried even clicking on the person, and other random things, even though there was no indication you could interact with them. On this play I did not try to do as much left clicking since you mentioned combining things and I thought I had done enough left clicking before and had nothing happen, and it looks like I must have missed clicking on things in the right order to trigger other items to appear, that then needed to be combined. There was no guidance on what to do, and as someone who doesn't generally play point and click games, I was lost. After I tried again I handed it off to my wife. She did manage to figure it out, and she'll write a reply with her thoughts.
I can't give you feedback as a point and click player, but as someone who is at least little familiar with them and general game dev, I'll try to offer the advice I can. This needs a lot of work. There needs to be some clue as to what to do, beyond just keep clicking on everything until something happens. There wasn't any indication you could right click on the person to use items on them. The UI in general needs to be improved to be more consistent and clear. After picking up an item with right click, right clicking in some places brings up dialog and keeps the item in your hand, sometimes you get dialog and the item disappears, sometimes it just disappears, sometimes it exchanges items. I'd start with a focus on giving players direction on what to do, and progress from there.
Also, I'd recommend doing a web build for any future jams. You will get a lot more plays and feedback from a browser playable version than download only. We only play download games, especially Windows only, in response to someone who rates and comments on our game, but we try to play, rate, and comment on as many browser games as we can. In discussions I've seen a lot of others similarly comment that browser games are all they play. I don't know GameMaker, so don't know how difficult it is to do a web export, but if you are going to do more jams, then it is almost certainly worth learning how to do it.