New Super Mario Bros. Forever (also known as Mario Forever) is a PC fan game based on Super Mario Bros. The game was developed by Softendo. The game reproduces classic styles of Super Mario Bros., with slightly different graphics and pieces of music from non-Mario games. The game has become popular, reaching the highest position in Platformer Games in CNET Downloads, receiving more than 10 millions downloads. As of late, it is the only game that can be accessed on Softendo's website as most of the other games (even ones not related to Mario) just all redirect to Mario Forever's page on CNET. 

Since the release of the fangame in January 2004 to the public, the game has become riddled with malware and trojans since it is now impossible to find a malware-free copy. The last patch was in 2013. If the user installs it, they will get a lot of PUP software downloaded onto their computer, which will slow it down greatly and make the game inaccessible, but it will remain on the user's computer. The only way to find a malware-free installer is by searching it on CNET. But they may have malware as well. After opening, the game becomes impossible to close out, and the only way to close it out is by restarting your PC.

Community content is available under CC-BY-SA unless otherwise noted.