https://smaghetti.com/creator/evanonline/ Here's my page if you don't want to read more. But I'll tell you what this thing is if you click the next two words!
Smaghetti is an online level editor for Super Mario Advance 4: Super Mario Bros. 3, which is one of the funniest real video game titles. SMA4 had e-Reader support, meaning you could buy packs of trading cards that had barcodes in them that could be read by the game and add new levels. The feature never took off, and only 38 e-Reader courses for SMA4 were ever released. And on top of that, only 12 of those ever made it out of Japan!
These 38 courses were eventually made playable to a wider audience when SMA4 got a Wii U Virtual Console release, which had all of the courses baked into the ROM. There are a lot of new assets implemented just for these levels - because the first 3 Mario Advance games were... Super Mario Bros 2 USA, Super Mario World, and Yoshi's Island, there are tons of assets plucked from those games and stuck in Super Mario Bros 3 with very little change. It's... very "fangame" feeling. Very sprite comic. These levels are weird, and Mario Maker almost definitely has some of the e-Reader course DNA in it.
However, it only takes a cursory glance at TCRF to see they had plans for many, many more e-Reader levels, as there's tons of assets for these that never got used by any official stages. Enter Smaghetti! I had kind of idly wondered in discussion with a friend earlier this year if anyone had ever thought to make custom levels by jacking into the e-Reader framework. I was expecting some "generate a barcode and scan it in real life" level stuff, but instead I found out that as of this very year a dedicated developer has been creating a comprehensive online level editor. As someone with a huge fascination with the e-Reader, I gotta say I love this.
Smaghetti's own about page gets more in depth about this stuff, if you're interested. https://smaghetti.com/about/
It's taken me a bit to find the time, but I finally managed to make something in this using some of the unused assets, particularly the Arrow Lift from Yoshi's Island. The spinning ball you step on and it goes in whatever direction you land on. It doesn't work so good! Luigi's jump is way too high to make using these things fun! The camera, weirdly, scrolls down so that your plumber of choice is focused along the top of the screen! It took some doing to make a level that used those darn things without feeling downright cruel! I'm glad they never used this in an official course!
Mario Maker 2 is one of my favorite video games ever, so I'm definitely interested in using this more. It's not finished, and I don't think it's reasonable to expect the same things out of Smaghetti as one would expect out of Mario Maker - but it's already a very fun little thing to use. A different toybox from the one I'm used to using, we'll say.

