Mega Man X: Corrupted is a Flash fan-game by JKB Games. The game uses the retro 16-bit graphics and SNES-like music of the Mega Man X series. However, the game also differs from the original series by being a Metroidvania-styled game where X and Zero can level-up and earn skill points to power up their attacks and weapons.Official progress updates, answers to questions, and the like are posted by JKB Games on their Facebook page, and although the game itself is still unreleased, it has a fansite here.
Tropes used for this (upcoming) game:
Acid Pool: Loads of them abound in Vulpex's laboratory.
Contractual Boss Immunity: Subverted with the Neuro Spike. While bosses won't turn to your side like mooks will, the Neuro Spike can still disable Collision Damage temporarily, and some bosses become vulnerable to their own attacks, as well.
Counter Attack: Jikūgeki (Time-Space Strike), which allows Zero to do a Flash Step behind the enemy and slash them. It only works as a counter to attacks and projectiles, though.
Multiple Endings: The creator has said that there will be 12 different endings. Some of them involve the order in which the bosses are fought in.
Orcus on His Throne: Averted for the eight initial bosses. They're out actively pursuing their goals (though still back in their boss rooms when it's time to fight) and will have an effect on the world depending on which four you initially take down.
Original Flavor: The Maverick bosses are original and based of animals not used in the games.
Spread Shot: Homing Missiles can be charged up and shot out in a spread of seven. The Plasma Bouncer's regular shot is a dual diagonal shot, while the charged version shoots a spray burst in many directions. The Hydra Armor's buster piece affects the spread and amount of bullets with its charge level rather than the power and size of the bullets.
Wall Crawl: The Crystal Bomb creates crystals that scale walls, while the Tank Ride Armor's grenades can do the same, too. The EMP Spark also runs across walls and ceilings similar to the Plug Ball, except that it can be detonated to send out lightning bolts to the opposite side. Zero's counterpart skill does a similar thing, by shooting a lightning bolt upwards that splits when it hits a ceiling.
You Can't Thwart Stage One: The last four bosses that you defeat will be able to carry out their mission and alter the world somehow.