Super Mario Bros. X features some modes that make the games easier/harder. They can be acessed via cheating or options in level testing.
God Mode[]
Cheat: donthurtme
Probably the best of all. It makes you immune to any hurt, even lava(PS: It don't work if you fall propusely into a hole.
Grab All Mode[]
Cheat: stickyfingers
You can grab any NPC you find.
Show FPS Mode[]
Cheat: framerate
Shows the frame rate on the upper-left corner of the window.
Max FPS Mode[]
Cheat: speeddemon
Probably the worst. Makes the game force the FPS to max speed.
Walk Through Walls Mode[]
Cheat: shadowstar
Creates a colorful circle around you and allows you to walk through walls.