I have memories of watching it a few years ago (I was a kid then) in the early 2000s probably; before 2010 I think. It was a movie with giant robots, and the enemies were aliens piloting what I remember as giant, more animalistic robots. I remember those animalistic ones running on water. The aliens themselves were a little taller than humans but mostly humanoid. I remember what the aliens look like a bit; most of the movie they were clad in some kind of armor, but the scene I mentioned showed one's face, if I remember well, grey skin, vividly green eyes, a beard made of some kind of quills, bald.
I have this one scene that stayed crystal clear in my memories. The heroes had captured an injured alien, and other aliens attack to, in the end, just retrieve the injured one, leaving with this one without attacking further this time.
I also remember the aliens going through a city in some machine (I'm actually not sure this one was piloted though) and destroying anything it perceived as a threat, from cars to security cameras.
My memories are coming from years ago, so I might be wrong in a bunch of things there, but this one scene, I can assure is correct. This might remind a bit of Pacific Rim, but it isn't. (It's watching Pacific Rim that reminded me of this movie.) It doesn't seem to show up on any giant robot movie list on internet, weirdly, so I hope you can help me.
And now I'm starting to wonder if there was really robots on the heroes' side. Maybe it was warships (sea ones, not spaceships). As I said it was some time ago and I was young, so bad memories are likely.