Update 10
Not much to report today, which is a good thing! All the programming is nearly done, and I've been putting energy into making puzzles and adapting the test puzzles I made during development.
I have about nine puzzles ready to go so far. Something I have to think about is how elements are introduced. I'd like to introduce puzzle elements one at a time, giving two or three puzzles for the player to get a handle on each one, and then a series of harder puzzles putting things together to test the player and finish the game. So in designing puzzles, I have to think about both the difficulty curve and teaching the player. This is tricky!
I'm ordering puzzles as I go to get the difficulty curve right, but the problem is, I made the puzzles, so I know how you're supposed to solve them. The player has to understand how an element works, and then how to apply that element to solve the puzzle. What seems natural to me may be obtuse to everyone else. I hope the level select mitigates the problem of difficulty spikes, and I hope that the sidebar text in early levels helps players to get to grips with the game engine itself. I also hope this isn't read as a lack of confidence in the player! I'm trying to explain how to control the game, and what things are, without giving away everything you can do with them. This is a surprising lesson: it's easy to made a hard puzzle, but it's really hard to make a puzzle that's easy but not trivial, that teaches the player without patronising them.
Here's a puzzle screenshot, to break up the text:
(This puzzle has a much harder iteration where you also have to weigh down four pressure plates outside of the box!)
I did a bit of work on the game engine too. I started adding sound effects, using a function which checks if the jukebox has been muted first. I was hoping that doing this would be quick, but I've had a few problems. All the sounds are very loud, so I've had to fiddle with their volumes. I've had to completely rework the sound effect for clicking, which was especially loud and sudden, like being punched in the ear. Also the door opening and closing sound effects play every turn, so I need to debug that.
I also made a little victory screen, just a few paragraphs thanking people for playing the game. With this, the game engine is basically complete! I just need to fix some sound effects, maybe add a couple more for picking up keys, and do a test export of the game to see if everything works. Things are looking good for a submission on Saturday!