Really? I mean it's so hard to tell...
Is it? Maybe I'm confusing you because you think "limp" means there's something wrong with the legs. Actually, a limp is most noticeable in the head movement.
Just ignore the rest of the body and watch the head. See that rhythm: it bobs a little, then it bobs a lot; it bobs a little, then a lot; a little, a lot; little, lot, little, lot...
It's the same in Tabatha's edit.
Well anyway, I think I've eased up Richie's movement a little. Or at least lessened the limping.
OK, I've taken a closer look at it in an image editor. The animation has 8 frames, and the leg movement is pretty regular: frame 1 matches frame 5 (roughly) except with the other leg, 2 matches 6, 3-7, and 4-8. It's all good. (Actually, 4 and 8 don't match very well, which could be a bit of a problem in itself and the reason for this mistake in the first place, but let's focus on the more important part for now.) However, if you compare the head position between those "matching" frames, you see that they don't match at all: frame 1 is one pixel higher than frame 5, 2 is one higher than 6, 3 is one LOWER than 7 (so on the frame where his head goes down on the one leg, it actually goes UP on the other), and 4 is one lower than 8.
Unless one of his legs is longer than the other (i.e. he's limping), his head should be the same distance above ground when his legs are in the same position only switched. If you match the head/torso position between frames 1 and 5, 2-6, 3-7, and 4-8, the limp will disappear.