-If you have yet to play the game, do not read on, as there may be spoilers-
Sliderman is first seen as a creepy game similar to Slenderman, with creepy music playing as Sliderman blends into the foreground. this is quickly changed as the Slider music from Super Mario 64 begins, and the dark colours are replaced with a bright blue sky, small clouds and a rainbow road which Sliderman slides along.
Sliderman is an automatically sidescrolling game, where players must jump over gaps, scoring a point for each one they successfully jump over. The game gradually speeds up, making it more difficult to react in time.
An alternate game mode can be found by clicking the "Lex Wins" on the lose screen. It is the same as the normal mode, except sliderman can jump on clouds, and can also double-jump.