Reviews

Everything about this game is unrestrainedly stylish. Every character in it is stylish, the things that happen are stylish, the way they happen is stylish and the visuals are stylish as fuck. It's got perfect transitions, bold - wallpaper worthy - colours, seamlessly animated camera and character animation, and the most delayed title drop that has ever dropped. There's very limited interactivity, striding the line between endless runner (Temple Run) and rhythm game, and can in-fact be played entirely with one button and a thumbstick. Despite that limitation it packs what I would consider every possible variant of that control scheme into its hour-and-change runtime. There are first person sections, schmups, vehicle sections on just about every vehicle you could expect and none of these gameplay shifts feel wonky or off.
Sayonara is honestly the perfect length for this kind of game, plenty of time to allow for a buildup and as many creative ideas as they can cram in but not dragging on beyond the point where it has to change its core mechanics to keep fresh, with plenty of optional collectibles to extend that time if you fancy it.

The music reminds me a lot of PinOut (another game/album hybrid concept) in a good way and that's what the game will live and die on for you, if you don't enjoy the music (which I very much did) there won't be much here for you. My biggest complaint is that the way each segment hard cuts to the menu after the level is over makes the shorter songs feel like they're cut off just before getting to the good bit rather than working as build-up to the next level. It definitely seems like it's intended to be played all the way through uninterrupted and, after beating it the first time, you unlock an "Album Mode" which gives you the ability to do so and massively improves the transition between tracks.

I watched an LP of this before playing it and wish I hadn't because I think I would've appreciated it even more if I went in fresh, but then again without being sold by that LP I might've missed it altogether.

I've been playing video games since the early/mid-2000s, and I am ashamed to say that I don't recall ever finishing a 2D platformer, probably mostly due to the naive notion that they just aren't "worthwhile" or as “good” as AAA games. And when I finally did properly finish one such game, it turned out to be one of the best video games I've ever played, period. Inside takes the best aspects of 3 undisputed gaming masterpieces and brilliantly makes them its own, expands on them and in some aspects even transcends those games. From Half-Life 2, it partly takes the futuristic setting run by a fascist government/organization, as well as, and more importantly, the physics-based gameplay, and no less significantly, telling the story and propelling the narrative without resort to cutscenes or non-diegetic hints, rather doing so much more subtly through the visual, aural and level design. It takes from Portal 2, the environment: "the inside," the test tube structure which bleeds into and informs the gameplay as well as the level designs, and even the story, demonstrated best by and the ultimate goal of breaking out. And finally, from Bioshock it inherits the ever disquieting atmosphere achieved through masterful visual and aural design, and even more notably, the "meta-ness" of the game, materialized (as in that game) in the theme of control, which only really becomes evident towards the end, and even then just for the most observant of players. The alternate ending gives Inside an edge over even Bioshock, in how much it pushes this idea, and in that it proposes a “solution,” to the “recurring problem” that the proper ending of the game turns out to really be: the only way to beat the test is to refuse to play in the first place. 
To fully appreciate the merits of the Inside, one has to also go in depth about the groundbreaking use of the fine line that the game walks between being 2 and 3 dimensional, the subtle camera moves, the astonishing graphic design etc.