Don't call it Portal: that wouldn't do it justice. Antichamber is the most clever and worthwhile puzzler you will find.
Antichamber is technically a first person shooter, in the sense you shoot things in first person with a gun. Originally I heard complaints pre-release that there might be little enemies to shoot with it. The gun is so much more than that, as is the whole game. While I love Portal, the fundamental difference that elevates Antichamber is that there is no set way to do things. This doesn't mean open world, no this is as linear as it gets. However, in games like Portal you solve puzzles by placing portals and more portals. In Antichamber, solutions are arbitrary, random and beautiful. Rather than using some specialized centerpiece of technology to solve puzzles, like the portal gun, most puzzles are solved by trying new things. Do you want to get through that wall? You might try running through it rather than walking, or looking down rather than up, or going backwards or jumping or spinning or weird things you haven't tried before. Thankfully, there is no one around to see how stupid you look when you fail. But when you succeed, it is very liberating. However, Antichamber is able to balance this with incredibly subtle and creative hints spread in weird ways. Many of these ways are posters, which have a picture that changes to a saying when clicked on. The posters often display quips, and sometimes they are just that, but many times they double as a solution to a problem. Sometimes the name of the section you are entering will tell you what to do. So even though what you are doing might feel random, it is never uneducated.
Antichamber does have a special piece of equipment, a gun which shoots blocks. However, the gun is so special because all it does is shoot blocks, which, unsurprisingly, can do many things. You can build staircases and structures, though I would avoid going full Minecraft, can launch blocks into "locks" and do many things. The gun progresses through the game, going from blue to green to yellow to red, gaining a slight new power each level. The guns also help solve my self-dubbed "puzzle locks" which are puzzles that require inserting blocks into certain areas and moving them in a certain sequence. This isn't as fun as the rest of the open puzzles, but it definitely