Classic Blue Bomber, fan-made
The newest iteration of developer Peter Sjostrand's Mega Man 2.5D is out, and you can download it off the official site.
The 3.0 beta boasts new co-op and single-player stages, including Splash Woman and Quick Man. Overall it's looking pretty great, even if you completely negate the 2.5D art style -- playing a classic looking Mega Man game in full co-op is a dream.
Mega Man 2.5D [petersjostrand.com]