So, you have 7 moves to thwart an apocalypse. That's not much time, not enough to leave the building you are in. You explore the building for a very short while, learn something about the game world, then you die, and start anew; it resembles, for example, Rematch.
But, unlike Rematch, which is a parser game, Save the World in 7 Moves is choice-based. Therefore, you don't have to invent some complex and unobvious actions in order to win - all the options are explicitly given to you, and at first it seems that you can solve the puzzle by simple "lawnmowering": just go everywhere and try all the links - sooner or later you'll find the winning one, right?
Wrong. This game experiments with the choice-based format, uses a few rather unusual ways to conceal information from the player and makes you do things you rarely need to do in a Twine game.
Also, it's funny, light-hearted and somewhat absurdist.
I'd recommend (Spoiler - click to show)listening to The Song right after you finish playing.
1) The puzzle is neither too easy nor too hard. You can beat the game in several minutes - but it gives you a surprising amount of satisfaction for such a short playtime.
2) The sequence puzzle perfectly fits the choice-based format. When all the options are laid out openly in front of the player and they don't have to guess the right actions - how can you make the player think, create the element of surprise? By making them guess the right sequence of the given actions, of course.
3) The choice-based format perfectly fits the xenobiology puzzle. Imagine if you had to type commands you need here - like DISENGAGE CREMASTRAL HOOK - again and again in a parser game; Twine mercifully lets us just click the links.
4) The game gives you interesting feedback when you do things in a wrong order. There are 7 different ways to kill a pharate; there are 94 losing paths through every game cycle and only one way to win. But when your plan goes south, you always learn something new and put together a new plan in the light of fresh information.
5) The game's horrific nature is not just for the sake of horror. It suits another purpose: the creatures are so monstrous, evil and repulsive that the player isn't likely to feel sympathy and get attached; so they can experiment freely and sacrifice as many pharates as they like while trying to understand the logic of the puzzle.
6) It's well-written. Laconic phrases and preteritions let the player's imagination run wild; that's one of the strengths of interactive fiction, an effect which is hard to achieve in a graphic game.