Interesting concept to pull the D&D type of system / mechanics in as your battle system. I thought that some of the early battles were maybe a little too punishing for a single-party. I was doing sufficient damage so it didn't feel like too much there, but with only 7hp before leveling up the first time, it didn't take much time before we died and it sometimes felt like healing was pointless, since you basically had to do it every turn just to stay alive at all, but couldn't really get an attack in in between. A few extra points of HP would've done enough to counteract that, though.
Of course, this could just be because of my TERRIBLE luck with RNG on dice rolls, so take that with a grain of salt.
I was very appreciative of your note to BG below, since I thought I was stuck until I saw that.
Nice work with this and good luck with IGMC!