Basically, Antstream offers a massive catalogue of retro titles (over 1,300 at the time of writing) via a subscription model. You can either pay an annual fee of £39.99 / $39.99 / €39.99, or you can just purchase lifetime access for £99.99 / $99.99 / €99.99 (but this offer's only available for a limited time). You can then stream all of the games to your chosen device, including PS5 and PS4 in what sounds like the near future.
If you're wondering what games are actually part of the service, you can find a full list on Antstream's official site. The catalogue covers everything from the C64 to the PS1, although it's pretty slim pickings on the more... modern consoles.
There's also a selection of titles from old Nintendo platforms up for grabs, including the NES, SNES, and Game Boy. Oh, and there are 57 Genesis / Mega Drive titles vying for your attention as well. Not bad.
Have you used Antstream before? Might you be giving it a try on PS5 or PS4? Reminisce about your old favourites in the comments section below.