Bah...
Bear with me because my standards are on the high end because NG has seen better stuff as you know.
There were small errors with the sprites in their battle stance for example. Their feet weren't planted on the ground. Backgrounds are also important, as insignificant they may seem. Try adding one next time.
The characters just moved...Too..Slow...If that is the speed they walk, make them jump around more often. Or...if they don't have any running sprites, do your best to make your own. The battle sequence was largely repetitive...And that is kinda bad...
And seriously...if i were Luigi, I'd kick my adrenaline up a notch and GTFO of the way of Wario when he came by. That...just...didn't work well...because. Remember, you had Wario walk at that ridiculously slow pace.
At least you don't blatantly suck. A little more practice, I think you'll be fine, but I don't feel eager to see anything more from you.