I am nearly done with making puzzles for the game! I might still add a couple puzzles here and there but the bulk of the work is done.
I was curious about how many levels of each type (i.e. main mechanic) there were so I made this (approximate) chart:
The colors indicate main mechanics and the subcolors indicate relative difficulty within a mechanic. (Some levels use more than one mechanic, however...). The surprising thing for me is the large "blue" section, which is one fourth of the game, and which I added almost as an afterthought and didn't anticipate would be so rich, while some other sections didn't end up as relatively interesting as I thought they would be.
I am very happy with the result as every single one of these levels contains a unique idea. Luckily the 4D mechanic is extremely rich so I didn't have to look much higher than the low-hanging fruits.
It seems like I almost doubled the number of puzzles in the game these past seven months? The initial prototype had about 30 puzzles, which defined the basic rules and most of the mechanics. Then I fleshed out the tutorial section and added two main mechanics: two years later I had about twice that amount. Then I mostly stopped making puzzles (even though all the mechanics were set) to focus on improving the graphics (which in turn improved the gameplay), but I added a few puzzles here and there, and I had about 80. This final push increased that to around 140: I added puzzles to all the mechanics to fill-in blind spots and make the difficulty ramps smoother, then made most of the puzzles for two main mechanics and replaced a small mechanic that had been bothering me for a long time with one that is much cooler.
Now I will do a last pass improving various graphical things, while we work on making each of these puzzles and the rest of the game look and sound as good as possible.