I have an idea for a type of Level which are extraordinary. This includes negative levels (like -1) and more levels that go against the game's ordinals, and might exhibit more. Feel free to use this, as long as you give credit.
Here's some concepts:
Level 0 (Licorice Black): The game freaks out like 2^64, but it's not as bad. The background is entirely black.
Level -1 (Scaled to Gray): Everything is grayed out. Could be accessible from a secret in a Level 1.
Level -2 (Jolly Overflow): Candies rise instead of falling. They rise to lower and lower points as you take out candies until they rain from the top like usual.
Level -3 (Symmetry): One side is truly the flipside of the other here. Involves perfectly symmetrical gameplay.
Level -4 (Dithered): There is no such thing as a straight line here.
Level 2^64 (Breaking Point): At this point the game just freaks out. The gameplay keeps messing up, eventually becoming a nigh unplayable mess. One of the hardest levels due to it constantly breaking.
Level 1.5 (The Middlend): Whatever 1 and 2s this is between are, the game freaks out processing them both. Similar things go for other fractions.
Level nil (Expired): When trying to load this, the game will show the game assets for a second, before crashing. This isn't really a level, but a glitch.