Hey there! Awesome, glad to hear you had fun! Sadly, I lost the project files for "Cuit" with the death of my old hard-drive. "Back-Up" was sadly a term unheard of back then, apparently. So, sadly I cannot make any more changes to the game, but eventually plan on someday writing a sequel, which will be a bit more polished. But yeah, I'd say there's plenty more difficult levels to come after "Rollercoaster", some are really mind-twisters, like "Have Fun" or "Yes it's possible". Oh, but your "Edit" tells me you already beat them :)

All the best,

Edit: And yeah, there are a few difficulty spikes, but funny enough they are in different spots for different people (watched all the YouTube let's plays of it). And it was kinda hard to make a smooth climb in difficulty. If I tried that, most time I just ended up with the same difficulty but just with more nodes.