I'm giving in 4 and a half stars for one reason. I know you were trying to go for some shtick where the main characters needlessly kill monsters for treasure without consideration in action adventures.
But then you throw in that the goblins tell the heroes that they won't fight, seating them in neutral territory. At this point, normal game heroes would do quests for the goblins in order to gain money or fame which throws off any ideas you wanted to convey.
To put it bluntly, you started with an idea that never fully panned out, leaving us with characters who needlessly kill for nothing other than greed.
Now, the animation itself is amazing and I keep coming back simply because of how well everything was made. A lot of people ask for payback for the protagonists, but stories are never that cut and dry. Some people are just assholes and they get away with it. That's life. Maybe they'll never be vindicated, that's just how it goes.
Sometimes you simply have to enjoy something for what it is. Anywho, great work.