No offence, but that looks completely like the original sprite except for the grey pecker.
In-game one would have a hard time distinguishing between those two in the heat of the battle (as the only difference are some grey pixels).
Also that little change does not explain why it would have more health or something like that.
I think if you want to make a new enemy, change the base layout. The main strength or attribute of the villain has to be clear on the first glance.
So in this case, make it full-metal, or give the rider some metal armour, something that really stands out and draws attention.
Or design a completely new kind of enemy.
For some more information on this, go look up the TF2 design philosophy:
TF2 Wiki
If you don't know that game, shame on you, but I will give some brief description:
It's a fast paced, class based (Medic, Soldier, Sniper, etc.) first person shooter, with a comic graphic style.
While the general anatomic proportions are met, all characters are heavily stylized and exaggerated.
For example the Heavy Weapons Guy has massive health and wields a minigun, which does a huge amount of damage. Therefore he is a big, fat guy and his weapon also is, so you can clearly identify him in a crowd and quickly turn and flee.
The sniper on the other hand is very thin, like a wimp, so he looks kind of fragile and he also only has less then half of the hitpoints the heavy has.
I hope this helps
foxblock out
