(Note: Some people say this hack's overrated, and I agree with that. It's not nearly as good as it could have been. Just wanted to make that perfectly clear, heh.)
Update (12/24/09): A few minor bugs fixed and another known bug added to the Readme.
"A Strange Mission" is a hack that I've been working on for almost a year. It's rather short (8 exits), and it doesn't contain many fancy custom GFX, let alone custom music, but there's one thing that makes it special: Every level has a unique gimmick programmed with ASM. Kind of like "Brutal Mario", just not as advanced. For example, there will be the feature to play as Yoshi, doors that teleport you by scrolling the screen, and many more.
To be honest, I'm not completely satisfied with the final product. If I hadn't promised to release it on Christmas, it could have been better and more fun to play... Maybe that's just because I played it too often and grew bored of it, though. In any case, I'm glad this hack is finally finished.