Super Mario 64: Last Impact is the result of 4,000 hours of work by Kaze Emanuar, and it looks incredible.
You may know Kaze from other Mario hacks -- he recently also the horrifying mod that replaces every texture in Super Mario 64 with Toad's face, for example. This time, he's back with something bigger and more ambitious. Judging from YouTube uploads, the ROM hack has been in the works for at least a year:
Last Impact adds 130 new collectible stars, entirely new areas, enemies/bosses, and 12 new power-ups. To wit, during the trailer you can see Mario don the frog suit, and at one point, he even uses his Paper Mario ability to flatten himself and fall through a grate. Kaze seems to have taken cool mechanics, characters, and ideas from all sorts of different Mario games, and has packaged them into one cohesive world. It's very cool.
If you'd like to take a closer look at some of the areas featured in the trailer, I invite you to peruse this playlist, which showcases Kaze playing through some of the levels:
My favourites include a level where you go into a giant beast, as well as the casino-themed one. So far, from what I've seen, the levels are all elaborate and fleshed out enough that you can see why Kaze would have the audacity to try to improve on an all-time classic. He's clearly a super fan with deep understanding of what makes Mario games enjoyable.
You can download Last Impact here, and watch a tutorial on how to actually play it here: