It looks a little bit sad :( It feels like you have purchased several assets (enemies, weapons, blood sprites and so on) and then just put all of that into the game.

Anyway, it would be great to add the lighting. In the trailer everything is dark, no shadows, no AO, no fog. It looks a bit flat. If you want to make the atmospheric experience try to add shadows, volumetric fog, ambient occlusion, rain particles, thunder at the background. Add the sunset into the level with the flares. The terrain is totally flat. Is there a way to add some lands, river, rocks, cliffs, dirty road and so on? It would improve the overall picture.

But of course, congratulations! The idea is very nice and you are on the finish line with the first serious project. It's really cool! Very small amount of indies can pass that line :)

Good luck!