Interesting to see what Megaman would look like in a Doom Style first-person-shooter. :P
You did a good job getting the walls to resemble what they looked like in the original stages.
The game works well movement wise, but the game seems to have a few problems that if fixed would make it more enjoyable.
-The soundtrack is limited to only a single loop. The Megaman series is known for having memorable soundtracks, usually one for each stage plus a stage select,boss and Wily theme. Adding some stage unique soundtracks would add to the Megaman feel you were going for.
-The Mega Buster blocks the view of its energy shots. It is hard to tell sometimes if pellets are even coming out. They can be seen when quickly shifting from right to left, but straight on it seems like bullets aren't even coming out of the Buster. Moving the Mega Buster slightly to the right or left would make it so the player can see the shots coming out so they can see if they are aiming correctly at an enemy.
-The lack of sound effects makes it hard to tell if you are hitting something. Combined with the above problem of being unable to see energy shots coming out of the Mega Buster, there isn't much in the way of feedback within the game. In the Megaman games, there are multiple sound effects that let you know that if an enemy still isn't defeated after a single shot, you still are aware that you did damage to it. Adding sound effects for...
---Getting hit.
---Hitting a target
---Going from level to level.
---Defeating an enemy.
---Shooting the Mega Buster.
---Finding a stage item.
---Getting defeated.
---Healing with an E Tank.
---Beating Wily.
...would make the game feel less empty in the sound department and overall be better.
-The "Red Monster-Mechanic" gets up close to you and does damage, and that is to be expected from a physically attacking enemy. However when he gets you he seems to snag MegaMan. This is especially dangerous when you are close to a wall when he gets you. Upon being snagged, it is almost impossible to get away from him. I'm only able to escape him when I shoot him until he is defeated. If this was an intentional design choice then no harm done, but if this was something to do with the hitboxes getting stuck, then fixing this problem would make it less likely for the player to get trapped. He could also do more damage once this was fixed so that players wouldn't try to breeze past him in order to rush through the stage.
-The controls aren't shown in the game itself and are only below in the games description. Adding them into a controls menu on a main menu would make it so they could be seen within the game to add to the overall design.
-The stages mostly consist of bending 90 degree angle hallways. Seeing as you implemented the game into 3D, you could throw in some slopes or different directions of hallways. You could also throw in some branching paths with varying difficult. It would help to make each stage seem more unique.
-Losing all health restarts the entire game. The MegaMan games are BRUTALLY hard sometimes, but they never erased all of your progress. Adding a save point option every couple of stages would still make losing a punishment, but would make it so the player didn't have to go back to square one every time they lost.
-An opening cinematic would help add to the story you wrote down in the games description, seeing it get played out would be a cool thing to see.
-Upon defeating Doctor Wily, an ending cinematic would make beating the game more fulfilling, as going from beginning to end isn't easy. Adding a cutscene would help going through all the trouble of getting the items and winning more rewarding.
From playing the game I can see you're a talented programmer, it can't be easy making a 3D game. If you could team up with another artist and perhaps someone who is adept at making soundtracks for games...then I can see you making a really cool 3D MegaMan FPS.
Good work man! :P