A lot of attention to detail and excellent music choices. World is fun to explore and has plenty of different things to both introduce it's own atmosphere while also staying similar enough to core Mario 64 values. Highly recommend playing with friends for an added bonus of fun.
It is worth noting that the hack has some extremely challenging moments that don't compare with a lot of the easier tasks presented beforehand. It is likely exactly what pros are looking for challenge wise, but more casual enjoyers will definitely feel blindsided by difficulty spikes. Many of the harder parts of the game don't particularly feel great when executing as intended, though maybe my inexperience leads to me feeling that its janky. It can be skipped for the most part, but 100% completion will definitely have you on the edge of your seat in anticipation/frustration.
All in all, incredibly well made and I can strongly recommend this to both casual players and Mario 64 experts.