It will punish you for every little mistake and kill you for thinking you're safe and making a reckless jump.
when you enter a level, you will never from that point get a break. The only moment of rest is on the world map. The game demands high levels of execution and paying attention to everything going on in the game. you will be on each level for potentially hours and the progress might be slow. The game is absolutely brutal and unrelenting. It's really good, i will get that out of the way, this is in no way to say this is not one of my favorite mario world hacks.
Okay, first thing to get out of the way: the reproduction is perfect, there is not a single bad thing i have to say about the job these guys did with it.