Tiny Emus: play old games online without hassle

Tiny Emus has in-browser emulators for all the classic 8-bit systems, but also ready links for specific games so you don't have to spend ages tracking them down and configuring them.

Creator Andre Weissflog, via Hacker News:

The emulators are written in C(99), with some platform-specific bits written in Objective-C and Javascript, and in C++ for the UI parts (since Dear ImGui is implemented in C++). Apart from the WebAssembly version, Win32, Linux, OSX and iOS is also supported, but you need to compile those yourself

The selection's limited but Weissflog's really nailed the "just let me play" UI, so hopefully more's to come.