Inspired by one of the longest running game franchises, here is Rokko-chan. It's basically a Rockman or Megaman clone for the US market. I prefer to use Rockman as this was what I grew up with, us having family computers here in Asia.
Lookit those intense cute eyes... of death!
Anyways, everything is pretty much here. It has 8-bit tunes, 8-bit graphics, cute to bizarrely named robot masters, pellet shooters, mad scientist/doctor and yes, platforming goodness. All this is running on your internet browser, as long as you have flash enabled you are good to go. The controls are pretty tight and the keys can be re-mapped. I yet have to try a gamepad, it's on the FAQ but in Japanese.