Rendered at 100 samples in Blender, Cycles. No changes made in other programs:
Alternative Versions with different colour management, compositing ect.:
Textures are from CGTextures and I got the bio hazard sign off a wiki page (it’s under public domain)
Would appreciate any feedback!
It’s way too dark to give you any good feedback, but in general: try to make something bigger.
I tried it light but it just made it look happy and colourful which isn’t the effect I’m going for 
I’ll try again to see if I can make anything brighter looking but keep the tone.
Also, what do you mean by make something bigger? Do you mean add more detail and put more things on the screen?
This image is very intresting, and has a good story to it. the only bit of input I can give you is that if this was a sign, it would have a glossy look to it, and maybe you could put fire in the reflection or something. of course, it may be an old sign, and then it need a bit more wear and tear, such as grime and grit.
Try also using different lights with different colors, as green and yellow etc…
