Well, sometimes when you scour the net looking for things, you run into weirdness like this little game which was published back in March. It probably went under your radar unless you're Brazilian, but it is in all honesty a completed game and I'm not quite sure how it exists.
In Megaman: An Uncertain Future, you play as Blues with the added ability of a jetpack. Though the stages are very basic, they do offer some semblence of challenge, despite the fact that you're fighting horrible mock-ups with pattenrs that actually felt like time was put into them. The bottom line about this game, is that time was put into it. It's got a working save system, collectable letters, finishable stages and functioning Robot master powers. It also doesn't feature a charge shot, but a weird triple shot. I won't lie, there are some interesting ideas in this incredibly weird title. But I'll let you see them for yourselves.
Not the best Megaman fangame by any means, but it's done and works - so there's not much else to say that I can't say with a youtube video. Yours truly, is playing the game of course:
You can download or play the game through Yoyo games, if for nothing more than sheer curiosity. Again, I'm surprised that this not only exists, but that it's actually finished. http://sandbox.yoyogames.com/games/213627-megaman-an-uncertain-future
If I find any more rarities, I'll put them up.