A lot of people claim foisting modern graphics on older games just results in compromising the original's artistic vision. I am a chump who likes shiny things, so the release of Portal with RTX on Steam pleases me. It's free if you own Portal, but fellow chumps should be aware that it's not running too hot for everyone, with reports of crashes and literally too-hot GPUs. Ray-tracing does not come cheap.
This new, fancy version of Portal adds "hand-crafted hi-res physically based textures, and new, enhanced high-poly models evocative of the originals." That'll be why those red buttons looks so red, then.
More notably, there's also both ray traced lightning/reflection effects and DLSS upscaling support, including DLSS 3 - so, as resident RPS hardwareman James Archer will tell you, if you have a swish RTX 4090 or RTX 4080 you'll be able generate extra frames to counter the framerate-zapping impact of ray tracing.
Everybody else might struggle, with "Mixed" Steam reviews reporting both limp framerates and frequent crashes. The minimum specs call for an RTX 3060, which those Steam reviews say will net you a still-crashy 30 frames. A fair few say their GPUs are running rather hot, too. It might be best to treat this as a tech demo, and have plain old Portal downloaded for when a few stuttery glimpses at the opening test chambers make you realise you want to play the whole thing again anyway.
I just tried to play a bit with my GTX 2070, for science, and I couldn't even get it launch without crashing. Good luck!
If you own Portal, you can grab Portal with RTX for free from Steam.