Maybe not the prettiest screenshot but I've been working on a bunch of technical backend to the game engine for our puzzle game in preparation for the demo over the last couple of weeks. One of the things that is hard about a demo is making the the demo executable different enough from the main executable that it's hard to crack while still providing an example of gameplay. The way I approached this was to make a binary pak format that only the full game knows how to deserialize while keeping the levels that the user creates/downloads and the demo levels in a regular ascii .lvl file format.