Secret Maryo Chronicles is a Free Side Scroller Super Mario World like Game for PC. It works and functions much like Nintendo's official Super Mario Bros side scrolling game. Gameplay features include; power up boxes, ability to pounce enemies, save and load changes, etc. Similarities are close enough that I'd consider it one of the closest clones of the classic original Super Mario World game.
In addition to simply playing the game, it also ships with an in game editor (activated via the F8 key). The editor enables you to insert your own background image, insert enemies, insert power up boxes, change player start position and more. This portable game was developed in C++, runs under OpenGL, and is offered completely Open Source, under GNU GPL V3.
Secret Maryo Chronicles - Mario World for PC
Authors Website: portable game project page
License: Open Source
Download: You can get this Mario for PC Clone; Secret Maryo Chronicles HERE
If you find you enjoy this game, you might also be interested in checking out Mega Mario which is another great Super Mario Clone for PC.