@FITZFACTOR Awesome comment!
As Fitzfactor said, credibility is very important, and I think that for concept design, its all about credibility. Design is about making things work, and when going into the visual elements of design, it's all about the aesthetics. Its about making things look "right". And to make that happen, you've got to base things off reality, and logic, because that is how subconsciously think of things.
I think for your design, the weirdest thing about it is the very face-digestive system thing. You really have to ask "why" for this one. For example, plants don't really have digestive systems, but carnivorous plants kind of simulate one by using their very "mouth" to trap prey and dissolve them to absorb the nutrience. You have to ask, what it gains from this different approach; because remember, life has been on earth for billions of years, and there is a reason for why most of the animals have guts and organs in their rib cage.
In a way, I can see how this can make sense on your design. Looking at us; we don't have organs on our limbs, they are pure muscle, bone and blood. However, since we have our energy-producing organs in our rib-cages, its no problem, because the body separates the functions. And so; our arms and legs don't need to contain organs, and can do their function without any problems.
Following this logic on your creature, it would mean that it uses its ENTIRE body as a muscle to run extremely fast, leaving all of their organs in their heads. If that is the case, shouldn't the head have more protection? and if its supposed to run that fast, maybe its body should have wind-piercing shapes to gain even more speed? its legs would also perhaps need to be thicker, considering the amount of force put into running, and it should also have more structure in its belly as to hold it together when running (this is a quadruped, without proper muscles in the back/belly, how is it supposed to run fast without snapping its back?).
Now, there is some design that I like about this. Its a grass eater, and that becomes clear when you consider how fast this thing has to run. Its definitely running from something! A problem cheetahs struggle with, is the amount of energy they have to take in because of all the running they do. If they are unsuccessful in more than three chases, they might easily starve and die due to the energy used, without gaining anything. So perhaps this creature, uses its tongue, or tail to pick up food and digest it while its running? a perk of not having "guts" in its belly, is that the muscles wont interfere with the digestion during intense runs.
I also got another interesting idea about the holes in the chest. Sharks can't breathe unless they keep swimming, so perhaps this creature, since it only has pure muscle in its rib-cage, it uses the muscles' movements to pump in air, instead of having a hallow balloon inside them.
I'm also thinking that, perhaps this creature could utilize the acid used in the digestion to defend itself. Since it is already located on the front, this can be used to fend off hunters.
So I obviously changed a lot; I'll go over what I wanted to change. Sorry for the rough sketch!
I wanted the creature to feel stronger, and have a more robust body. However, I didn't want to lose the elegant look of your creature. So, I look at some horse references to give the creature a prouder and stronger body type.
I didn't want to MAKE horse though, and I saw that your limbs were quite different from that of a horse, so I looked at some Maned-Wolf references and tried to give the character, that tall, strong, looking shapes that these wolves have. Oh, and, I gave it hoofs, so it can deal with the fast running better.
Now, it wasn't intentional to make the head look snakelike, but you can call it a happy accident, because when I realized, I HAD to add a cute snake tongue. This also helped the design, because its supposed to be THE super-fast, uncatchable creature. With this tongue, it can sense the hunters even faster.
I gave your creature a mouth, because I stumbled upon an interesting design that kind of played along with an idea I had. So, the creature can use its digestive acid to defend itself, and that reminded me of this beauty from pacific rim. The idea is that, it uses its mouth to spray the acid. 
The creature has also four eyes, two of which have completely different functions. The one with the big pupils, is mostly used during nighttime. It is the bigger eye, so it can open the pupils even wider during the night, and take in more light, so it can see when its dark. The smaller eye is mostly used during the day.
And lastly, I gave it bat ears.. because why not.
Either way, my paintover is a bit more grounded, and kind of goes away from your lovecraftian, horror, alien like concept. But, this is only an example, so I hope it helped!
Just a last point; I like your design. Its pretty cool, and its ORIGINAL. Now, I don't know if you wanted it to be very alien like, but I feel like there was too much originality, or uniqueness in your creature. It is okay to take inspiration from others, or from reality!
Feb 16, '17
Jul 28, '17
I do recommend to study gesture drawings and constructive drawing. 
