Sorry, but this game just isn't good.
Movement- movement is slow and plodding. There isn't any of the up-tempo action that you can find in Mega Man or most FPS games (Duke Nukem, Doom, etc.)
Enemies- I think that I found 5 different enemy sprites. That about it. The use of Mega Man enemies is fine. No Sniper Joe?
Bosses- Thus far, I've made it to the end of one stage. No robot master? That's the whole point of the level select of the robot boss and the one staple of Mega Man games.
Visuals- Lackluster. You move through room after room of similar looking textured walls. Each level gets its own color palate and that's about it.
Music- One repetitive song that doesn't really fit into anything that you're doing. The song doesn't fit with a fighting motif. If you're going after a Mega Man crowd, you need to nail the music; also, the music repeats half-way through the song.
Sound-effects- There are none, whatsoever. You need to have something, whether that be the Buster firing, enemy getting hit, you taking damage... something.
Gameplay- It's just bad. For one thing, there isn't any indication that you are firing. If you press the Spacebar, you may get a pellet shot, you may not. If you hold down the Spacebar, the Mega Buster pulses, but you won't see any shot pellets. The pellets also look like they come from Mega Man's body, passing under the sprite of his arm cannon, which means that you can't see your shot. There's also no indication of whether or not you are doing any damage to your enemies, making the best strategy in this game to just bob and weave through the level and hoping that you run into Beat (sometimes get stopped just before Beat for no reason).
Overall, this game just isn't good. Sorry.