I really hate to give advice on a pic such as this, because I am just starting out using blender and 3d in general, and the most I have done is some lettering for a logo I am working on and messing with materials on UVspheres :-?, But (you just new that was coming 
) I agree with Humphery, if it was me I would try to give the lake of fire some perspective of mabey going on to the horizon forever. With the way you have the gate positioned and the sky (kinda looks like a wall) it looks as though they are in an enclosure, like a swimming pool. My only suggestion is to put somthing in the background to give it perspective (I dont know mabey some mountain ranges or something) and mabey have the lava/fire extentending over the gate in the background to show that it goes on forever.
Again please don’t misunderstand this post, I think this is a great pic, These are just my suggestions.
I bet the devil has a huge gas bill at the end of the month 
Well If you do go to hell you won’t worry about getting cold.
that looks really awesome! did u make them people models?
Yes and no. I found a simple model of a man and deleted his head. (it looked really dorky) then i fract sub 6 or 7 and and distorted the body to give the rips and tears. then i modeled a new head with his mouth open and stuck it all together. I then setup an armature skeleton and associated the vertics to the proper bones, but not all of them so that when i moved his arms up it streched his skin in places. (it acctually was an accident but it turned out really good.) then i applied the texture and gave it some bump and thats what you see. So yes and no
Very good improvement
Why not model Cerebrus, the three headed dog that guards the entry to hell 
Hi!
You can still increase drama in your pic: you need to modify your camera’s position, do not shoot perpendicularily to the gate; this flattens it in a terrible way. Try this:
Move the camera to the right (near the column), rotate it so you can see the caracters (well this depends on your artistic views, it’s your pic, i mean, not ours) and set the rendering to render in “panorama”. To do this, divide your X resolution by 20 and in the bottom left-hand corner of the rendering panels set the X-part button to 20.
Then activate the “Panorama” button under the “shadows” button in that same panel.
And RENDER!
This makes straight lines go slightly curve and gives a lot of volume to the pic
or maybe not it all depends on what you want .
Have fun