Antstream Arcade is a retro-games streaming service. You can play a variety of old arcade, game console (e.g. NES and SNES), and computer (e.g. C64 and Amiga) games. The games run on their servers and are streamed to your computer and they have controller support.

Although their 1000+ game catalog is mostly action games they do have at least one RPG (Temple of Apshai for C64), wargame (Pegasus Bridge for ZX Spectrum), and strategy (Premier Manager 97 for Sega Mega Drive), so you can play games that last more than a few minutes. A few games are available on multiple platforms.

You get 1000 gems to start with. Starting a game is 30 gems and once you've started you can keep playing for as long as you want. You can win gems or game achievements and in Antstream contests. There is a Premium subscription which is unlimited play.

I tried four games -- Elevator Action (arcade), Star Wars (arcade), Jumpman (C64), Temple of Apshai (C64) -- and unfortunately mostly unplayable due to lag. The games look great though and definitely nostalgic. I'm on Sonic Fiber Internet so apparently you need a better Internet connection than that. Still you can download and try it out for free to see if performance is good enough for you.