Ignore the Slinky HUD, level, and background. I haven't gotten the chance to change them yet. All of my games now are built off of Slinky. Walljump controls have been changed and made easier to perform. I will add updates to SotSK, Slinky 1, and Slinky 2 and add a toggle for this new walljump control after NSMB4 releases.
Preview of Mario's expanded moveset in NSMB4. In NSMB3, you can only jump and use powerups. In NSMB4, you can now crouch, spin jump, midair spin, walljump, groundpound, and use powerups (not made yet).