Celeste [official site] is simple enough. It's a platformer about climbing a mountain in which you can jump, air-dash to clear larger gaps, wall jump, and hold down right-trigger on the controller to cling to vertical surfaces until your stamina runs out. You leap between platforms, you avoid the spikes, and it's all very pleasant.
That's how it begins, anyway. By the time I reached its third area, the last included in the preview build I've been playing, I'm fleeing from mirror-world clones of myself that mimic my movements and destroy me on touch and navigating the world via blocks full of colourful stars. With each twist introduced as I climb its mountain, Celeste climbs higher in my estimation.
I should have expected as much. Celeste is being made primarily by Matt Thorson, the indie developer responsible for the excellent single-screen multiplayer platformer TowerFall, which I reviewed in 2014. Celeste benefits from the same attention to detail that made that game feel so great to play, but initially seems to lack an exciting hook to match TowerFall's bow and arrow.
No single hook presented itself over the course of my time with it, but it introduces new ideas across each room which force you to attain new levels of mastery over those abilities I mentioned above.
Your air-dash is crucial to clearing obstacles, but can only be used once before needing to be replenished by landing on a horizontal surface. This makes the early rooms - the world doesn't scroll till you arrive at the edges of each screen - about reaching the next bit of safe land. Then common complications start to appear, such as safe land that disintegrates after a few moments beneath your feet. Then come blocks which move along a track when you grip to their side, the momentum from which can toss you larger distances without the need to air-dash if you time your release and jump correctly.
Then there are gems floating in the air which, when touched, replenish your air-dash immediately without your feet needing to touch the ground, letting levels cram even more spikes on to every other surface as you never need touch the ground. And so on until you're traversing the world via those star-filled blocks I mentioned at the start, which are solid until you dash against their surface, at which point you are absorbed into them and propelled out the opposite side at speed, your dash again replenished.
It seems sensible to assume that later stages will continue to introduce new twists on the level design. None of those featured so far is in themselves remarkable - there is nothing about their design which seems as clever as, say, a Braid world - but that's not the point. Celeste isn't a puzzle-platformer or any other kind of hybrid but that more rare occurrence: a platformer which is very simply about jumping and the skillful application of jumping.
This sounds nuts, but look at the platform games released over the past five years and you'll see that this isn't true of most of them. There have been a thousand 2D platform games which use jumping as a form of traversal, but they tend to primarily be about something else. Roguelikes, RPGs, crafting games... the jumping isn't the point. When the jumping is the point, it rarely feels as good and as satisfying as it does in Celeste. In 2016 we've had N++ and Flat Heroes and that's about it.
Along your your climbing journey you'll meet other characters, with whom you can have brief, linear conversations. These include the jovial fellow mountain climber who is there to take photos for their not-Instagram account, pictured above, but also antagonists, people from your past (you are not called Celeste, the mountain is), and more. These provide moments of respite between the increasing difficult and tense platforming.
While it lacks the finesse of the full game, you can get a little taste of what makes Celeste fun by playing Celeste Classic. It's a version of the game made in PICO-8, a "fantasy console" which exists only in software and comes with a creative suite for making games you can share via your browser. Celeste Classic was made in four days and it features the core ideas including the mountain framing device, the air-dash, jump pads, powerups which refresh your dash.
There's also very briefly updated devlog on Tumblr, which has some nice artwork but which I am linking mainly in the hope doing so will spur it into life. Otherwise the full game is due for release sometime in 2017.