It's an OK first project. Not amazing, but not unplayable. Just making an something with no plugins and gives the player a complete beginning-to-end experience is a good way to break into game making.
I'm glad I saw the comments about talking to the party while invisible; I almost quit the game there. Navigating by clicking got me the rest of the way through the game. Trying to budget enough time to thoroughly playtest before release is always a challenge!
While I'm glad there are no random encounters, the maps seem excessively large. Making maps smaller and more efficient has a lot of benefits, such as making it easier to detail, ease of guiding players to the next point, and cutting down on playtesting time.
Battles are pretty basic. There are a lot of skills at the start, but they are straightforward enough that it's not hard to figure out what to use. It would have been nice to start with fewer skills and have the party gain more by levelling up from battles. Since there aren't many battles, the length of each fight seems to be just right.
The writing could use some work. The characters talking over each other seems to set up for something, but it's not clear what. Are they trying to avoid the sensitive topic of Harold's absence? Is this just Marsha's personality quirk? Is it a joke? The overall narrative does a fine job of staying focused on the fact that Harold scarified himself and the party is trying to deal with that loss. The plot point about Therese disappearing doesn't seem to be quite right: didn't she disappear right in front of the party? They act like she just wandered off. And then during the fight with the goddess the whole party is with Therese, but when she gets back to the foot of the mountain the rest of the party joins her and can see her.
So in all, it's a fine first project that could use some improvement. I hope these points help you as you grow as a developer.