From the point of view of realism it may be right to have fast spinning fans. But from the point of view of a player the fast spinning fan creates a blinking shadows / lights effect that may even cause seizures in some people. I have no idea why they did it. In horror / thriller movies or scenes it's common to have shadows from spinning fans but they aren't that fast. With night vision on it's even worse, the glare blinds the player and it's the way the player has to go.

Misaligned textures are the sign of laziness or carelessness. Very often misalignment is unavoidable, but if those spots are hidden in the shadows, dark or behind other geometry nobody is going to notice it.

This sci-fic setting in DNF is ugly. There isn't contrast in the textures themselves apart from some normal mapping and lines. The fluorescent light on the wall has both a strange shape and a texture that glows more at the center of it than on the borders.

The nuclear symbol that serves as a duke's trademark glows like fire. The orange light is right in terms of duke nukem's trademark, but it's completely out of place in the level. It even glimmers like a candle in the wind, which is completely nonsense given the sci-fic setting.

The textures themselves lack personality. There isn't a clear identity. It feels bland, tasteless, generic metallic panels that convey no meaning at all.

There are shadows here that come from nowhere. It looks as if they didn't recalculate the lights after changing something. That or somebody just though that the shadows were pretty or appealing. Now I can't know for sure the reason behind those out of place shadows . I really have no idea what they were thinking.

In the beginning of the DLC expansion they didn't put much attention to lights and shadows. There are some very noticeable mismatches.

Detention Center mission. There is this room which servers as an obstacle because the player has to shoot that target to unlock the doors to pass. I don't know what the level designer was thinking to make the room full bright and white while the rest of the detention facility is mostly black and dark. Maybe they were thinking on some sort of decontamination room or some sort of a security room. I really don't know.

Research Facility mission. I have no idea why is the room dark when there are so many lights here. From the point of view of contrast it may look pleasant, but I have no idea why is the room dark. This game uses sector based lighting but that isn't an excuse to mismatch textures and lighting. To make it worse, the same lights in other corridors in the same level make them much brighter.

Chapter 5. Fire without light doesn't exist. Better say, some chemical reactions do produce fire without light but that's a different story. For some strange reason there are candles with fire but no light. In chapter 10 there are red alarm lights inside the ship that are way too small for how much bright they are. In chapter 14 there are over-bright candles. The light is too much bright.

Chapter 10. Why is the sunlight shinning inside the ship? Are the walls transparent? Inside the ship the sunlight is shinning on some walls and doorways, highlighting paths while at the same time, important paths are hidden in the dark. Before venturing inside the ship the player has turned off a power generator, which would explain the lack of lights inside the ship. However, that's not the case as there are some lights on inside the ship. Light in this level feels illogical.

Chapter 16. The blue lanterns are out of place. These Chinese lanterns are originally red. For some unknown reason there are blue ones in the level. Blue light is both incoherent with the Chinese style and out of place because the whole level has a dusk atmosphere and hue.

The light sources in a level must match the architecture. A light of one type should have the same color and intensity across the level to keep things consistent.

Chapter 13. These green orbs are proximity mines that harm the player. The first time the player encounters them they signal a new type of enemy that is a walking toxic bomb. What the game does wrong is to not follow that pattern and the green orbs show up again when the walking bomb enemy isn't placed nearby the mines. Sometimes the mines don't even signal danger ahead. They are just there to invite the player to follow that way. Why not use the green light sticks that already exist? Even the green light sticks fail to follow a pattern and aren't always placed to guide the player where there is no other light source. Sometimes, the green light sticks were placed at random just because the green light is pretty.

Level 11. In here the player finds a new weapon locked inside a forcefield. The energy beams have to be turned off and if the player go to each side they'll find a device to be destroyed that shut downs the energy. In regards to unlocking the weapon the game does a pretty good job in having an environment that the player can easily understand what to do. However, why is the forcefield holding the weapon red? The energy beams are blue, there is no reason for the bubble to be red.

On the background there is a wall with what seems to be a hatch or door, highlighted with a blue light. Textures and lighting in a game must be meaningful to the player and not misleading as it is this case. That wall has nothing there, it's just a wall. 

The game fails to be coherent in regards to signalling open and closed doors. In general the pattern is blue for open and red for closed, which also matches the pattern of traffic lights around the world. However, the game doesn't always follow this pattern. That giant door has a red light meaning it's closed. After the player activates a certain control panel the light stays red, albeit flashing.