I played the most recent demo (which you should probably put in the initial post btw, so folks don't have to search for it through the topic). I'll put my thoughts on what I played here.
The demo itself was pretty glitchy. I sequence-broke and got to the end right after the party splits up. It thought I had three party members despite only having Squiggly in the party, so I checked the area I didn't have access to before and it took me right to the end. Afterwards I backtracked to go see what I missed in New Meridian, and I got into Lab 8, but couldn't interact with Double or Big Bass, which I don't think was intentional. Afterwards I found Eliza but the dialogue during her battle kept looping infinitely. If you travel left or right on the beach, it also loops the screen until you enter the cave. And characters sometimes used the wrong dialogue at the end of the battle (i.e. Parasoul exclaiming she is hungry and hopes the enemies dropped something to eat).
The spritework is nice, but the sprites have less colours and shades than most of the other things in the game, which is a little jarring. You can definitely tell the difference between sprites made specifically for the game and the sprites used from RPG Maker's default stuff. Innsmouth's background was a little weird, too. Having some characters with transparent portraits in-game and others with a solid coloured background was also weird.
Speaking of RPG Maker default stuff, an RPG Maker game using default things from it makes it feel like just another RPG Maker game, where a custom tileset (while time consuming to make) gives a game its own identity. OFF was an RPG Maker game, which I didn't know during my first playthrough, because it used all custom stuff.
Some areas don't have music, while some places swap music when you enter a building. Too many music changes in the overworld causes the music to lose its mood. Some of the area transitions were also weird, like the one from Innsmouth directly to New Meridian. The beach area and the first town had a nice, natural transition with the cave. There are more ways to do this, though.
I dunno if the jokes were just for the demo, but things like the Homestuck joke and fourth wall stuff was a little overdone, and I feel it detracted from the experience overall. If you want the players to be immersed in the Skullgirls world, taking them away from it will break that immersion. A few references here and there never hurts, but too many does.
A lot of grammatical errors in the dialogue, too. But that was mentioned already.
Overall I am excited for the idea of a Skullgirls RPG, but this doesn't feel finished. And it might not be, and that's okay. Keep at it and work on improving things overall and you'll be golden. I may contribute to the project, we'll see.