I bought that game. It’s not really a ‘game’ where you can interact with the world. There is no goal, and nothing to do. You just walk arround. I would not pay more than a dollar for that game 
SMBX (free)
There is a Super Mario Clone called ‘SMBX’ for PC. It was made a long time ago by the maker of Terraria, and features many Nintendo characters and sprites from many different nintendo games (not only Mario).
There is also a 2-player-coop mode (on one screen).
Original Text:
Super Mario Bros. X 1.3.0.1 is a massive Mario fangame that blends elements from Super Mario 1, 2, 3 and World. It has many power ups, such as the Ice Flower, Hammer Suit, Tanooki Suit, Kuribo’s shoe, The Billy Gun, and Yoshi. You can also play the game with a friend in the 2 player co-op mode, where the screen seamlessly splits and combines as the players separate and rejoin.
