Why slow? I liked it better fast. If you're going to do it so slow you'll neeed to make inbetween frames and possibly subpixel animate at that. Harder, but it might look better. You need almost subliminal movement, if you're going to do it slow. Faster is more 'campy' but it works better for a videogame, perhaps?
I have to say I disagree with the way you've shaded the ground tiles themselves a lot now, but it's something that if I saw it on a game I would learn to live with. Just an aesthetic consideration.
I feel like I need more animated light around the tank now.
Absolutely, by the way. Don't be afraid, you just need a few variations to make the animation work. Do it, it'll enhance the effect very much.
Also another idea. The 'rim' of the tileset, the scaffolding around the tiles, I suggest you try this trick. Duplicate the palette entries and give them complementary tints (complementary color to green and cyan and blue and purple on the color wheel are the exact opposite), so make the border of the image warm while the interior is cold. It might mess with the red tint you have on the walls however, so if you try this, remove that tint (I know, it's hard to remove something as cool as that, right?). So the rim has a complementary palette and pops up, shows elevation and cradles the composition.
It might look like ass, but it's worth a try!
I really like this, I just wanted to say
