I really like this. Mainly because it's an idea I've tried to do myself of years, I just haven't got around to it for a while. However, my idea didn't involve miniature figurines. Mainly for one reason: A game called "Power quest". It's a rather unknown GBC game that i managed to pick quite a few years ago. The gameplay is strikingly similar to this. Small robot figurines that you upgrade via shops and you go around and defeat opponents in RPG style. Your game has a lot more freedom though, which is a big plus.
Could the overhead style by chance be inspired by the Megaman Battle network games? I see a lot of similarities, there's also the pokémon-esque badge collection. Still, they are all games I enjoy. I'm not accusing you of anything, just saying you've got good sources. The Power Quest similarities are interesting though, even if they are by coincidence.
Anywhoo, I've tested the game. I have to say, for using Multimedia Fusion you've got a pretty solid battle engine. Something to improve on in your next game are the combo attacks. I can hardly execute any special attack at all past the regular hadouken attack. The double button attacks rarely work and I have yet to do a super attack. Also, there are times when I can't damage the opponent at all after a series of hits. Unless it returns after the opponent decides to punch me, I am doomed to loose the match unless I've got time on my side. Apart from that, there's hardly anything technical to complain about as the game is pretty well polished. (There is of course the text that goes beyond the text box, but meh...) I do wish that one could walk around and explore rather than battling in a room until said boss gives you a badge, but that's just a suggestion.
OK, so on to the pixel art.
I actually quite like the way you made the 'duels' in the fighting mode. There are a few things that break up the style though. For example, there are no shades. Yet, sometimes there will be powerfull highlights or eyes that have barely visible shades. At times even the outline has a different colour and that breaks the pattern. The backgrounds have already been covered pretty extensively, so I'm not going to analyse them right now.
As for the overworld, it does suffer from a lot of equal colour hues. Most of the time, the colours rarely vary in contrast and everything sort of merges together. I had a very hard time seeing the faces of the people in the game due to this. If you could increase contrast on the outlines a tad (not too much though) and use shadows where needed, it would be lot better on the eyes. And as a side note, the hero's hair is very pillowshaded.
That said, I really enjoyed playing the game. If the next one turns out even better It'll be a sure download on my side. Keep it up!