All directions have noticeable gliding.
It's very difficult to get a 2-frame animation without gliding, especially with larger sprites like this. The bigger your sprites are, the more frames you'll need for the motion to look good. There are two factors to avoiding sliding:
1. Having enough frames that the character moves very little per frame. e.g. if a character moves 10px per cycle of animation, they'll move 5px per frame in a 2-frame cycle, but only 2px per frame in a 5-frame cycle.
2. Positioning the feet in each frame according to the character's movement speed so that the feet appear planted. For this reason, it's important to settle on your characters' movement speed(s) before you start animating. There is no one-animation-fits-all solution for anything other than hovering xP
In older games the 2-3 frame walking cycles looked passable because the resolution was sufficiently slow that the character rarely moved more than 1-2px on the screen for each frame of animation, so there was no noticeable sliding. A lot of GB/GBC RPGs had animations like this, the common thread being ~16x16px sprites.
Another method for slightly larger sprites was to have 3-frame a running (not walking, not 2-frame) animation, so that the middle frame had the character completely off the ground, and that frame lasted longer than the ones with a foot on the ground. That way, most of the sliding happened when the character was off the ground, which looked natural. You can see this in some SNES and GBA RPGs. Of course, that doesn't work for walking, since when a character walks, they always have at least one foot on the ground.