Concept is good and the layout of the hotel was well done. What I would like to see most is a full screen button since I had to zoom out really far to see the whole game. There is a check box on the Edit Game page that allows the game to have a full screen button, so if your software doesn't just shove the whole game to the left if it is in full screen (my only major complaint about the current version of GDevelop), I would definitely recommend checking it.
My other suggestion (if it was not already on your to-do list) is a trash can for leftover items when customers give up and leave -- I had a whole bunch of order papers just sitting on the table I had to move to the side. The trashcan was a feature I really appreciated in an old flash game called Penguin Diner, which I found to be a very well done restaurant type game. It's still playable on CrazyGames, so I'll share the link in case you are curious.