Just as in the good old days but now it works in a browser.
The latest version is 0.6. Apart from the emulation there are the built-in assembler to write and compiler a code for Intel 8080 directly in the window of the emulator, and the almost interactive disassembler to view not only a code but also data.
A few screenshots (click-able):
Emulator (“Volcano” game):
The list of games is also being updated.
I do support only Chrome really but they say it also works in Firefox and Safari with more or less of little glitches.
It is difficult to explain my fun from this project. This is something deep inside.