Indeed the area is waaay too red. Use lightning with care and place it on the right places.

The white lamp shouldnt have that big lightrange, make it so small that it just doesnt touch the walls and the ground. It will look like its turned on, and in real life the lamp wouldn't make such an odd white spot on the wall.

The textures are often cut off (for example, the roof, that thing above the gate, the floor in the second room. Make sure they fit in your environment, and be sure not to use too much repetition. With standard textures is ment that you used alot of them from the standard.wad. They just look very unprofessional and gives your game that blocky empty nonrealistic feeling .

And, yeah, dress your rooms with stuff, models, make it less empty.