Okay, so I managed to reduce the data size by about 40%. If two of the same characters appear after each other, it'll replace it by one character, but capitalize it. Since this data needs to be uploaded as a string anyway, this only reduces the data size as a result. I think optimizing things like this, packaging the same info in less data, is a super nice puzzle to figure out. I did something similar to Mobility's replays in the Box Kickers X's level editor, trying how to save what is an array in-game as a save-able string.
In the meanwhile I'm having another little dilemma. I even stepped in at the Indie Dev Hour for opinions. As listed before, the game has multiple difficulty levels, Easy, Normal, and Hard. Normal is the experience the game is designed around. Easy simplifies it by making it easier to activate the platforms, and makes this even simpler if the player is having trouble. Hard is the opposite, all checkpoints are removed and platforms appear shortly after they are used by the player, and is severely more punishing. Another earlier post in this dev log describes it in greater detail, but this is enough to understand my problem.
The problem is the naming convention. Hard should actually be called something like 'punishing', since it actually steps up the difficulty by quite a bit from Normal. Meanwhile, Easy should have a label like 'Beginner', but it mustn't make the player feel that he is a beginner (or 'noob'), but making him free to use it if it doesn't work the normal way (some people have that tendency against handicaps, accessibility features, or Nintendo's Super Guide). 'Normal' indicates that it's the intended experience, so that name is quite okay, unless I find something better.
It might seen as a little detail, but it's quite fun to find a solution for it and the final product will definitely be better thanks to all these small design thingies. I'll let you know if I figure out some good names.