Antichamber

One of the best first-person puzzle games. Albeit quite a bit more minimalist compared to Portal and The Witness, it is easily just as clever and interesting. Uniquely mind-bending and fun!

If you liked portal (and who doesn't) you'll probably like Antichamber too. It's an incredible puzzle game that plays with non-euclidean space and plenty of other tricks that challenge your preconception about how space is supposed to work. Many things feel confusing at first but they behave consistently and it feels very satisfying to learn the logic behind them. Especially because the game often has you go through previous sections again which often are slightly different depending on which direction you approach them from, or because the game "tasks" you with smuggling something from another puzzle through. You do need a bit of perseverance though because sometimes it isn't entirely obvious where you need to go to to progress next, or you have to re-do sections because you borked a puzzle and need to reload the area. Though this time you spend there just creates a weird sense of familiarity with the white halls you've trodden through so often. Together with the oppressive loneliness and silence this actually makes new rooms feel a tiny bit scary at times since you're leaving familiar space.