Portal 2 Is the Closest Thing to a Perfect Game, and It’s Now 15 Years Old

Valve’s masterpiece is still Portal 2, a brilliantly designed and incredibly funny puzzle platformer. Originally released on PC on April 18, 2011, and later on other platforms, Portal 2 improves upon the already excellent original Portal, offering a flawless puzzle experience. Even after 15 years, it’s difficult to find games with a more refined design, sharper humor, or better overall execution than Portal 2.




![In CsV3Sb5, a kagome lattice material, the emergence of an odd-parity [latex]f-f[/latex]-wave charge order breaks both [latex]C_{6z}[/latex] and inversion symmetries, opening a gap at the Dirac crossing near the Fermi energy and modifying the electronic density of states-a phenomenon that expands the established phase diagram beyond standard charge order and superconducting states.](https://arxiv.org/html/2604.14538v1/Figures/FIG05.jpg)


