The Super Mario Flash Series of a games consists currently out of 3 games.
Super Mario Flash (2007)
Super Mario Flash 2 (2011)
Super Mario Flash 3 (2016)
Super Mario Flash
Super Mario Flash, also known as SMF1 for short, was the first official SMF game to be released in the series. The game is assumed to be created using the assets, code and engine of Super Christopher Bros, a joke game where an MS Paint like sprite goes through levels that are almost identical to the ones found in the official SMF1.
Super Mario Flash 2
The follow up to SMF1, which this time around is based around Super Mario World, instead of SMB-All Stars, although it still uses some SMB-All Stars elements like the font as well some elements from Super Mario Bros 3, like the Airship and the Boom Boom boss sprite. SMF2 is considered very superior to SMF1 thanks to its smooth physics, advanced but easy level creating, custom background & music and practically no limits to what you can do in your levels. The game is currently still being actively updated by Chairo.
Super Mario Flash 3
Super Mario Flash 3 is a game build off SMF2's engine, but this time around developed by Hiro, which is why it seems very similar. However, it includes many new elements, for example one-way gates and temporary !-switches and along with the graphics style being themed around Super Mario Advance 4, it definitely sets it apart from SMF2.