Nice stuff man, i really like that turret and the axes!
I also think that some of your concept work suffers from being too detailed so it becomes noisy. The same applies to the textures, they have a lot of small and very sharp details which makes them hard to read. It might look cool in a close-up, but you should keep the big picture in mind.
Zoom out and look from a distance, this helps a lot. It's all about the big shapes and silhouettes, then the detail.
Detail is cool, but it makes all the difference where you put it. If you have the same level of insane detail everywhere, it just gets confusing and doesn't help the design and readability.
Give the eye some nice big shapes to follow and then have some detailed bits there, just in the right place and not on everything.
I think that you could push your work a lot more if you put some more thought into functionality. I know it's a lot of Scifi stuff and it needs to look cool, but too randomly placed panels, cuts, lines etc. quickly make a piece unbelievable.
Take the last panel as an example - it looks cool. But in terms of functionality, it just doesn't make a lot of sense to me. What is its function? For a floor, it would be unpractical with all the little intendations. Very hard to clean and easy to stumple. For a wall panel, the little drain- things doesn't make much sense.
No need to overdo this and get into rocket science, but as a concept artist you should think more about things like this. Which makes your work much more believable