critique wanted need feedback on WIP animation of Spike

[HereComesTom 2,267]

I know I want Spike as an NPC in my fangame, so I found some frames of Spike walking in profile (it was from the Inspiration Manifestation episode, where he's just let Rarity keep the spellbook and is walking to the right when Owliscious stops him), and I found some images of Spike standing next to the mane six for a size reference.  Putting together what I had, I created this animation from scratch:

 

http://lookoutherecomestom.deviantart.com/art/WIP-preliminary-Spike-walk-animation-587626544?q=in%3Ascraps%20sort%3Atime%20gallery%3ALookOutHereComesTom&qo=0

 

It's incomplete; if you look closely, Spike doesn't have any arms.  Before I committed myself to an animation of him, I wanted to get some feedback about how well I did and whether I should change anything, in particular, the bobbing---I know that animations of a character walking need to bob up and down a bit, otherwise, it looks like they're just suspended in midair and swinging their legs.  Did I do a good job with the bobbing as it is?  I have him go one pixel down on frames 2, 3, 6, 7, and 8 (out of 10).