Not sure it's actually sliding. It seems your movement is just delayed a few frames which makes it really ugly. If you fix that it would probably look a lot better. You can always adjust the walking speed if it doesn't look right. It's hard to tell from a video on a black background though.
Do you have a constant playback speed for your animations? Some of them seem faster than others. It's possible the original game didn't always have the same number of FPS for the different animations. You could play around with that too until you are happy.
I am not sure what you mean constant playback speed for my animations. But I can tell you that the type of animations uses different intervals because some have more frames of animations.
I just realized this after pasting the code, but the more frames for that type of animation, I needed to use a smaller value for the interval. The less amount of animation frames, I needed to use more larger values for the interval.
private int idleAnimationInterval = 3; private int moveAnimationInterval = 3; private int attackAnimationInterval = 10; private int shieldAnimationInterval = 10; private static final int numberOfIdleAnimations = 10; private static final int numberOfMoveAnimations = 12; private static final int numberOfAttackAnimations = 7; private static final int numberOfShieldAnimations = 4;