I bet that we all know and love Diablo, the original one. Blizzard North as the developer and Blizzard Entertainment as the publisher launched this game back in 1996 for the PlayStation. Back then, it is the go-to hack-n-slash and mouse-destroying title of very gamers. Now you can enjoy it right from your browser.
The game is set in the kingdom of Khanduras (a fantasy area in the world of Stanctuary). You will take control of a character to go against Diablo. Under the town of Tristram, the player travels through sixteen levels to eventually face Diablo and his lackeys.
A Rivsoft project
This port to the web is a Rivsoft's great work. They also have worked on many Blizzard-related projects before, such as BlizzGet and DotaReplay. This port allows you to play the shareware edition of the game. However, if you have the files of the original Diablo game, you can use that to access the full game.
According to the project page, 2 programming teams use the source code of Diablo to "reconstructed" this port while keeping all the bad code and bugs from it. If you already own the game ( you can get it now on GOG, by the way). You can upload a specific file in the game folder to the browser to access the whole game.
A quick play
Though the shareware edition should be fine if you just need a quick game: it features 2 areas in the dungeon and one character class.
It is sufficient to just jump in and play for about 15 minutes: with no hustle of starting up a Diablo game. There will be no scrolling dialogues, overlong cutscenes, and no fanfare. You just pop up on the town, walk slowly to the nearest dungeon, then start the murdering.
Check this exciting port of the first Diablo right here.