Mushroom Kingdom Fusion

It's one of the things that inspired me to develop game ideas, including a mario-centric crossover game (similiaritys to mkf end here basically). and now i am actually developing a game myself (a monster rancher fangame)

it had some flaws though, some later levels got too long and bosses/minibosses had too much health.

The sucking fucking thing couldn't even run properly, SMBX was better until it got covered with faggot shit.

What happened to SMBX?

Well OP, Mushroom Kingdom Fusion Classic was been canceled–for good. What had once a substantial development team dwindled down to Lars Luron and Del. Team mismanagement in the past had caused MKFC to get bloated with content it didn't really need and has basically made the source a large mess. The inability to find the cause of bugs, real life obligations, and burnout combined were a fatal blow to the project.
I hope that answered your question, OP.

I was one of the original team members.

Simply put, the game was getting too big for its own good. Quantity was being accepted over quality as long as the enemy/level that was added was from a video game, team members started putting in their own "original characters", and there was no direction on what the end result should be, especially after the original creator, JudgeSpear, left to work on Super Mario Fusion, because he got sick of the community.

It was impressive how much they added to the shitty engine they were using, but it was never going to get finished. Game Maker is also fucking terrible for team development, considering you have to re-add all the changes that a person makes.

It was a glorified fanfiction that had a community involved, which never ends well. They tried to add a story to tie everything together that would make the Subspace Emissary look like Citizen Kane. Oh yea, and the art style (if there even is one) was a mess. People were too blind to see that their sprites looked really shitty when compared next to SMB3 Mario.

It was a really ambitious project but the creator leaving the project before it's complete is like 99% sure of being the toll of its death bell. Shame, too, since I was interested in seeing how Kirby would be handled.

Redigit more or less abandoned it in a complete state (I remember there being claims of a D&C from Nintendo but given it's still available to download from its main site, still being worked on by fans and Redigit made Terraria afterwards that's likely not true).

Kirby, if I remember correctly, was going to get power ups based on the enemy's elemental type. The problem was there were so many different enemies that it would have taken forever to categorize every enemy.

I think everything wrong with the game's new level design can be found in the Fever Las Vegas level.

Along with the many playable characters that didn't fit in the game(Arthur not being able to jump on enemies) the level design was also getting horribly amateur, to the point they started modifying perfectly fine levels by JudgeSpear into a bunch of meme garbage
with unfitting mini bosses and removed content. Compare the old Babel's Tower to the new one.

That's kinda cool

Can't find any footage. You got any, user?

They made shitgraphics pack like Undertale, sonic.exe, MLP and maybe FNAF.