Critics note that searching for "MarioNES 1.5 download" often leads inexperienced players to malware-ridden sites, and that the hack’s attempt to mimic official naming confuses younger retro gamers about what is real.
If you want to see the physics in action legally: MarioNES 1.5
Despite the name, it wasn't a "Mario game" but a general-purpose NES emulator. Using Mario's name was a common tactic for hobbyist projects to immediately signal their purpose to gamers. MarioNES 1