Since we are not forced to create a game with 3DGS, I spent a look at a 2d adventure point and click development kit.

Have a look at http://www.visionaire2d.net/index.php?newlang=english

I thought of creating an adventure game, which is a mixture between the movies HOSTEL and SAW. For example game begins in a dark room, where player can not get out, before solving some puzzles, etc.