Although it’s really nice to start seeing some actual “game” homebrew for the PS4, there’s a strong caveat. It’s basically clear that this game was built using some leaked build of either Unity or an official PS4 SDK, or both.
In other words, the regular tinkerer who tries to stay on the right side of the law will not be able to build that kind of homebrew game yet (but feel free to play it, I guess). Not until a real, open source PS4 SDK (with enough support for input and graphics) sees the light of day.
The developer distributing the game is also implicitly admitting to having the leaked SDK in their possession. There are many legal ramifications to that, I’m not a lawyer but if you ever want to be involved in the creation of an open source, reverse engineered SDK for the PS4, it is probably important that you do not touch any official PS4 SDK with a 10 foot pole. Just my two cents, not actual legal advice here.