I particularly don't like the blue shade they chose for the background. It's a frecking blue sky. Who ever heard of that.
I'd say Super stardust's sprites were the best. Lionheart is my king of the backgrounds and flashback has got to have the best flowing animation of characters. I loved the way you could draw your gun, crouch, roll over an edge to drop down behind an enemy, turn around to face enemy while he's turning, raise your gun into aiming position and fire. It's just great.
Out of this world (http://hol.abime.net/?id=2328
)had some nice animations too. I still like the part where you get picked up and shaken around a bit, kick the guard who drops you, run over grab gun turn and fire as well. But flashback still gets my vote for best motion.
Problem is you can't have everything. Something is sacrificed to make room for something else.
Personally I was impressed by alien breed 2's graphics as well (http://hol.abime.net/?id=3233
). Clean stylised graphics without too much rastering or imitation of detail. At least none which failed to work and just ended up annoying the eye instead.