Well, I doing criticism like this for the first time, so here... we... go!
Onto the legendary birds...
I like the Articuno one and the Zapdos one. The other... no. NO. It looks unnatural, and to top it off, its pose looks strange. You should use a Starly or something.
Now to the Houndoom... (I had to whip out an R/S one to compare.)
Well, well, this is a good revamp. But if you start comparing it to a real Houndoom... Yep. The nose should be longer, and the legs... longer too please. And actually, I just noticed, the Houndoom... doesn't look as fierce as it is now... Maybe the sprite WAS meant to be like that?
...Sneasel.
![[PokeCommunity.com] Sneasel's random sprites [PokeCommunity.com] Sneasel's random sprites](https://archives.bulbagarden.net/w/upload/a/ae/Spr_3r_215.png)
![[PokeCommunity.com] Sneasel's random sprites [PokeCommunity.com] Sneasel's random sprites](https://archives.bulbagarden.net/w/upload/e/e8/Spr_4d_215_m.png)
Now on to the comment: What the hell IS this?! The colour isn't even close, and I even whipped out the DPPt one to compare. The colour should be the green you see in swamps (or the blue you see in... er... dark waters), and there's no shading on the blackish part. You should, and MUST, remake this.
Don't get discouraged though! I'm an amateur at spriting myself (but that doesn't mean I have no sense of "art", if you know what I mean), so let's keep it up!