Rockman 4 Minus Infinity is a Rockman 4ROM hack by a Japanese person who goes by PureSabe.While otherROM hacks tend to just make the original game harder or alter it in a few ways and little else, this one ascends beyond this status to turn the original game into an incredible experience. The staggering amount of new content include new level designs, bosses, features, weapons, music, enemies from other Mega Man titles, Shout Outs to other video games, and more!This site contains lots of information on the game.Robot Masters
DCN-025: Bright Man, weak to Homing Control Ring Boomerang, gives Spark Manbow
DCN-026: Toad Man, weak to Pharaoh Shotgun and Toad Spell, gives Toad Spell
DCN-027: Drill Man, weak to Water Cutter and Hell Wheel, gives DrillTorpedo
DCN-028: Pharaoh Man, weak to Drill Torpedo and Hell Wheel, gives PharaohShotgun
Artificial Brilliance: If you use Rush during the Snatchman battle, the doppelganger will use it against you. Yes, you can end up healing the boss when you're low on health! To really rub it in, it still uses your weapon energy.
A.I. Breaker: Using Recycle Inhaler to trap Snatchman in an E-Tank, however, gives Rush back to you. You can use this to One-Hit Kill the boss with Rush Cannon.
Puresabe seems to be a big fan of Rockman World 5 and Mega Man X2. The Cossack bosses are based on the X-Hunters and the Charge Shot looks like the Charge Shot from X2. Some of the enemies and gimmicks from Rockman World 5 show up.
Reaching the third Chimerabot in Wily Stage 4 without taking damage for the entire game has Shadow Man destroying it with a Diagonal Cut.
Baleful Polymorph: Toad Man's Toad Spell, when used by him, turns you into a defenseless frog from Kaeru no Tame ni Kane wa Naru. When used by you, it turns enemies (and items) into tiny, harmless toads.
Berserk Button: Pharaoh Man gets upset when Mega Man destroys the statues in his stage and later challenges him to a battle when Mega Man destroys the coffin in his room.
Critical Hit: Happens on occasion. Get the Super Star from any Shadow Man encounter by finishing him off with a Recycle Inhaler, and the chances of this increases.
His final appearance drops the ?Dagger, which makes every hit critical.
Damsel in Distress: Mega Man has to break Kalinka out of a cage (guarded by a Copy Roll, of all things), in order to advance in Wily Castle stage 3.
Dead Character Walking: A variation - if you die while using Hell Wheel, the wheel keeps going (along with the camera). In some points you can even get to the next screen this way (though you obviously can't do anything)!
End Game Results Screen: The game calculates your "hero score" based on a number of factors (i.e. if you rescued Rush and Beat or sucked up Eddie with the Recycle Inhaler, or getting all the secret items), with Proto Man giving a comment based on what you did wrong (if you did anything wrong).
Evil Knockoff: Snatchman in Wily Stage 2. If you beat him once, he steals 4 of your Robot Master Weapons with the help of Dr. Wily's Stealing System.
Feed It with Fire: Dust Man, with anything except Toad Spell when he is using Recycle Inhaler.
Multiple Endings: The ending of the game has several permutations depending on your actions:
If you rescue Rush during the final level, Mega Man will use Rush Cannon on Wily's space ship upon escaping the castle. Otherwise, Mega Man will collide with the space ship instead, destroying it regardless.
Eddie, Rush, and Beat make appearances depending on if you used the Recycle Inhaler on the former and/or rescued the other two during the final level.
If you turned Toad Man into a toad during the rematch and spared him, he will appear in the first part of the credits, hopping alongside the train.
Depending on what happened to Rush, Eddie, and Beat at the end of the game, they will appear either in color or grey in the "Presented by Capcom" screen.
Mythology Gag: There are a whole lot of enemies from other Mega Man games, for starters.
The lifebars/HUD from the Game Boy Mega Man Classic games (also known as the Rockman World series) show up for the first half of Bright Man's stage. They also appear when fighting the Wily Capsule and the Petit Robot Masters.
Holdable Control Ring Boomerang gains the Power-Up Magnet abilities of its Game Boy version.
Drill Man's stage contains Ring Man's hippo Mini-Boss, which has the blocks of its Game Boy counterpart.
Oh Crap: Shadow Man get this reaction after defeating him as the Bonus Boss in Wily Stage 4 when his smoke bomb that he used to cover his escape every other time fails to go off. To rub salt into the wound, it then does go off moments after he explodes.
Also, Shadow Man. The "final" fight against him is pathetically easy, but his Bonus Boss appearance is much tougher.
Turns Red: All of the Cossack Robot Masters have a more aggressive "Pinch" mode that activates when they reach critical health, complete with pallete change and faster music, with Pharaoh Man notably taking this to extremelengths. When you refight them in Wily Stage 3, they are already in their Pinch mode behaviour, but retain their original palletes and music.
Use Recycle Inhaler on Eddie and he turns into a Energy Splitter. However, do that and Eddie won't give you any warnings for Cossack Stage 1 and Wily Stage 2 or show up to give you any powerups in the other stages. Proto Man will even lament his loss in the post-credits results screen.
Proto Man: Your rookie ... Eddy. It's regrettable about him. I've never expected that his core have not found in the ruin of Wily's fortless. ...! Are you trembling? I see... as I heard that his signal disappeared near you, you saw his last moment... didn't you? Don't mind, you had done best effort to him.
A lesser example can be done, in Dive Man's stage; the Up'N'Down enemy wears a scuba diving mask for its appearance there, but if you shoot it off, it will drown and explode.
Eleventh Hour Superpower: However, if you find yourself losing said final battle, Proto Man comes in to give you the Wily Buster and refill all your health. The Wily Buster shoots charged shots instantly and reduces all damage taken from the Petit Robot Masters.
Womb Level: The area after Wily Capsule definitely invokes this feeling. As expected, it turns out to be an illusion.