New Levels

-Molten Underpass (1-24) [GladiaCloud]
-Shanghai Showdown (2-12) [Fosterkmas]
-Zeppelin Flight (2-18) [GladiaCloud with help from TaXMaN]
-Prehistorik Isle (2-S3) [GladiaCloud]
-Mystic Plains (6-1, combining Verdaint Plain and Mystic Forest's layouts) [GladiaCloud]
-Mana Caverns (6-6, Partially reusing some of Blue Mountains' layout) [Fosterkmas]
-Chrono Chaos (6-S?) [Fosterkmas]
-Lava Powerhouse Zone (7-11) [Fosterkmas]

Revamped Levels (All level revamps are by GladiaCloud unless otherwise stated)

-The Entryway
-Goomba Mines [Fosterkmas and GladiaCloud]
-Boo Mansion
-Subcon Panic
-Lake of Amnesia
-Birabuto Bash
-Koopa Cove (Previously Lakitu's Cove) [Fosterkmas]
-Shroom Lagoon [Fosterkmas]
-Tree Zone Trek
-Dinosaur Mountain (Previously Dinosaur Land)
-Rice Beach
-Dire Dire Docks
-Frosty Flight
-Glacial Caverns
-Frozen Plateau
-Frost Palace
-Grassland Outpost
-Sky Tower
-Castle in the Clouds
-Isle of Mystery
-Bay of Flames
-Dungeon O' Doom
-Dry Bowser's Crypt (Previously Dry Bowser's Castle)
-Hell Prominence
-The Grand Canyon [Fosterkmas]
-Skyscraper Domain
-Fever Las Vegas
-Ancient Citadel (Previously Aztec Citadel)
-Jungle Shenanigans [Fosterkmas and GladiaCloud]
-Sahara Scramble [Fosterkmas]
-Egyptian Tomb
-Serengeti Safari (Previously African Safari)
-Himalayan Peaks (Previously Mt. Everest)
-Persian Dungeon
-N. Sanity Island
-Outback Track (Previously Transiberian Trek)
-The Highlands [GladiaCloud and Fosterkmas]
-Scandinavian Campaign [Fosterkmas]
-Military War Zone [Fosterkmas]
-Yellowstone Journey [Fosterkmas]
-Pomplona Stampede (Previously Running of the Bulls) [GladiaCloud, Dooki51, Fosterkmas]
-Industrial Nightmare [Fosterkmas]
-Wretched Tundra
-Foresaken City [Fosterkmas]
-River of Flame

Removed Levels (Most levels removed here are because certain revamps make them redundant)

-Nighttime Icecapades
-Airship Armada
-Verdant Plain
-Blue Mountains
-Moscow Malady

Major Changes

-Waluigi has been added as a new playable character
-All NPC dialog is now stored internally and the NPC dialog system has been revamped to remove a lot of superficial variables
-Revamped most of the game's sound effects to sound better (Special thanks goes to +Zircon and EddyMRA [formerly Judge Spear] for helping identify and/or locate some sounds)
-Converted several stereo sound effects to mono due to them taking up unnecessary space
-Brick blocks now always use the correct shard sprites
-Fixed not always being able to hit blocks when right underneath them
-Collecting a 1up with the amount of lives maxed out now gives rupees instead
-Added the Duke Nukem suit for Wario and the Bill Rizer suit for Waluigi (Sprite art done by Toxicghost with the initial concept created by Kibbleknight)
-Roll now keeps her momentum when using the Tango jetpack after doing a slide jump
-Megaman can now only use the jetpack boost once but is able to create up to two Item 1 platforms with the Rush Jetpack
-Fixed the broken hitbox for Roll's charged up hunter shot and increased its damage against enemies
-Item 1's slot as a subweapon has been replaced with Needle Man's needles
-Replaced the Doc Robot miniboss in Construction Site with Dust Man
-Fire Mario now has a visual indicator for holding a charged shot (this may be removed if it's deemed unnecessary)
-Ported the weather systems used in GMEA
-(GladiaCloud) Fixed broken parallax scrolling values in many levels
-(TaXMaN and Dooki51) Added world-specific level completion text sprites
-(TaXMaN and Dooki51) Swapped out a few more music tracks and added loops
-(AuraLancer) Revamped Star Man's boss fight
-(Mario123311) New map sprites for Mega Man and Proto Man
-(Toxicghost) Fixed the servebots' sprite colors
-(Kibbleknight, Dooki51, D-Turbokiller) New world warp portal sprites
-(No Body, Kibbleknight, GladiaCloud, Obreck2, CrappyBlueLuigi, Del, Sudtrap, Fosterkmas, Dooki51) Waluigi's sprites

Minor Changes

-(TaXMaN) Fixed the enemies in the Whispy Woods fight having glitchy collision
-(TaXMaN) Fixed the rockets fired by worms facing the wrong direction
-(TaXMaN) Fixed a bug where red coins wouldn't be saved properly
-(TaXMaN) Fixed the Metal Slug dicokka tanks getting stuck when destroyed with certain objects
-(TaXMaN) Reprogrammed the Resident Evil licker enemies to use fewer objects
-(TaXMaN) Fixed ceiling-bound enemies not turning around properly
-(TaXMaN) Reprogrammed the steam objects in Lava Powerhouse
-(TaXMaN) Fixed Sir Kibble getting stuck
-Fixed respawning guns repeatedly respawning after completing a level
-Fixed certain guns playing two sound effects at once
-Fixed the ammo meter for guns not disappearing after death
-Fixed a rare bug where powerups would stay stuck in the air
-Cleaned up the external backgrounds a bit to remove a few repeated or unused backgrounds

Behind-The-Scenes Changes

-Terran Marines and Alucard now use the NPC system instead of using special objects
-Revamped the world 6 chest system 
-Revamped the brick skinning system to be a lot more simple to use
-Revamped the level numbering scheme to remove a lot of archaic restrictions. Level numbers can now be any desired string.
-Revamped the blue brick skinning system to be a lot more simple to use
-Revamped the player warping system so that now there is no maximum for the amount of position changes to be made in a level
-Revamped the midpoint system to be simpler and less bug-prone
-Moved the alarm for spawning underwater bubbles to the player objects rather than in the camera object
-Deprecated the player headmarker object
-Removed some unused code from Roll's object
-Removed a lot redundant or unnecessary code from the autoscroll object
-Moved some player goal related code from the goal player object to the flagpole object
-Finished separating out Waluigi's sprites