There are appropriately 7 separate categories for New 'N Tasty, in which Any% and 100% are the majority to run.

Any% entails that you complete the game as quickly as possible (defined by attaining the ending cutscene of the game) by any means necessary through glitches and exploits.

Any% NMS is essentially the same as Any% except using glitches and exploits are not allowed. NMS, or No Major Skips, means you cannot use major glitches such as the Death Delay Glitch to beat the game.

100% entails that you must save all of the Mudokons in the game, all 300, using glitches and exploits however you wish.

100% NMS is essentially the same, meaning you must save all Mudokons in the game, though you cant use major skips or glitches.

Good Ending implies you must save the minimum amount of Mudokons to achieve the good ending of the game. You must save at least 50%, or 150.

Maximum Casualties (Major Skips) essentially means you must complete the game having killed as much Mudokons as possible.