Hi! The game was made with Adventure Game Studio: https://www.adventuregamestudio.co.uk/site/ags/
It's a great choice if you want to make simple point-and-click games, but it's also very old and has many limitations compared to more modern engines (such as lack of support for Unicode, so it's pretty much impossible to make games in Chinese with it, for example). It is free in any case, so you could always give it a try and see if it suits your needs :)