Though Nintendo won't be happy and will shut down your video as you use their IP as happened many times before. Some months ago, someone did the exact same thing with Unity engine, and his Youtube video and website vanished within two days. 
Nintendo's upcoming NX console (successor of Wii U) will hopefully be more powerful than PS4/X1 at the end of 2016. And hopefully we get nice reboots of Super Mario 64, Mario Galaxy, Maria Kart and Zelda.
 Edit: I found the HN news from 3 months ago: https://news.ycombinator.com/item?id=9276605 -> https://roystanross.wordpress.com/super-mario-64-hd/
-- the website now reads as follows: "The project is no longer playable, or downloadable in any form. I received a copyright infringement notice on both the webplayer as well as the standalone builds. Which is fair enough, really. In light of Nintendo recently making a deal to release some of their IPs on mobile platforms, it’s probably not in their best interests to have a mobile-portable version of Mario 64 sitting around. In any case, I didn’t really expect for this project to get so popular, and was hoping it would function primarily as a educational tool and a novelty. (...)"
Yeah, I wouldn't count on that.
But this is really just a typical game mod. Someone made some models for Mario and coins and put them in various UE4 tech demo scenes.
That's not to say it isn't cool. it just isn't extremely interesting from a technical perspective, besides the amazingness of UE4 in general.
- all the environment assets were taken from the Unreal marketplace
- all the character actions were scripted using blueprints only
I've never actually developed for the UE, just read about it.
I'm in the throes of learning F# and didn't want to muddy that up by learning C++ at the same time, so thanks for alerting me to that.
edit: Hm, looks like it's unsupported as of late. A bit disappointing. May still be usable, but I'll have to dig deeper to make sure it's not a total PITA
edit2: And it seems that they've nuked the download page as well as the git repository. Oh well.
What about trademark? Could the author sell it?
See what happened to Super Mario 64 HD (an attempt at a remake with unity): https://roystanross.wordpress.com/super-mario-64-hd/