Neat game! , though I have some comments that might help:

From the screen shots, what I think is that the textures could be more detailed... using some small photoshop/GIMP tricks might do the thing.

Also, instead of making the explosions translucent, try solid explosion shapes with their normals flipped. That would look cool. Smoke is good too.

Some normalmapping/bumpmapping shaders would do wonders, though thats alright if your computer cant handle it with a high enough FPS.

The ground definitely needs detailing

I very much like the HUD though, it is awesome.

I hope my comments dont strike you as too negative, I REALLY like what I see in the screen shots. Giant robots are awesome.