The lovechild of Super Meat Boy and... Splatoon?
In a day and age where 2D platformers are abundant, developers have made sure to include some form of gimmick in each new addition to the already populated genre. In the case of INK, this manifests itself as a focus on color. The elevator pitch for this game reads something like "A tough 2D platformer where the levels are invisible until you splash color on them". Said splashing of color occurs when you walk on things, when projectiles explode and when you double jump. At first, this is a novel concept that forces you to be careful lest you fall into a bottomless pit or run into a spiky wall, but the feeling quickly wears off when, in true frustration platformer fashion, you inevitably die a whole bunch (thus readily revealing the level in its entirety, since the color is persistent between deaths) before beating a given level.
INK is a simple, but hard, game. The only input options are left, right and jump. The game starts off easily, slowly introducing you to the concept of revealing a level through splashing color before adding other elements such as enemies, pits and the like. The enemy design is frankly lacking, with only 3 enemy types across 75 or so levels, and gets stale well before you're through to the end, but some clever level design partially makes up for it. Some levels require you to pull off platforming feats worthy of the best of them, leading to some truly satisfactory moments.
A comparison to something like Super Meat Boy is apt - both use (mostly) single-screen levels that are relatively short but hard, both move at a brisk pace and both restart you instantly after death. Additionally, there are no lives or game overs, you just keep going until you're there, number of deaths be damned. Something that is lacking in INK though is the moment of cathartic release when you finally beat a level. In Super Meat Boy, this is where the game shows you all of your combined attempts leading up to the climax of hitting the end point, whereas in INK you promptly get booted into the next level.
This is a short affair, likely to last 2-3 hours, which is one of the only reasons it gets away with the level of monotony, and while the visual style is unique, the novelty of its gimmick is short-lived.