Invasion of the Mantle Dwellers is RabMoghal's first effort, and it's flawed but not bad. The intro is probably the most effective part of the game, where we're introduced to the concept of the mantle dwellers, vaguely humanoid creatures made out of meat who inhabit the earths mantle and have been peacefully coexisting with people... till now!
Our protagonist is convinced that people can communicate with them and that the crisis can be resolved peacefully. His ship is slowly surrounded and then destroyed by the monsters, and he barely escapes to town with his life. It's a neatly scripted sequence that sets the tone right away and gets us up to speed on the information we really need to know. Once ashore, he goes to tell his master at the dojo about losin' the boat, and asks the King's permission to get a new one. The dude is dedicated to a peaceful solution!
Some of these middle scenes are a bit more tedious due to weird usage of one time NPCs. Guys disappear after you talk to 'em, or weird roadblocks present themselves till you jump through a particular hoop. In one really weird instance at the end of the demo, a man tells you where to find your boat and blocks access to the inn. When you go to your boat, the captain tells you the seas are too rough to sail tonight, and that you'll have to wait things out... at the inn you just left! After spending the night at the inn? Back to the boat you go! It's a sequence that could definitely be streamlined.
In another kind of weird sequence, you can fight the King's guards as a sidequest, presumably meant to test their skill. It's good world-building, but because they disappear after you fight them it kinda feels like you're killing the new recruits. If a second NPC popped up all "OWw, gee, you won!" I think it'd feel a little better.
The hero speeds are slow, and early in the game you're pretty puny. Fortunately, you level really quickly and are one or two-shotting your opponents before the end of the demo so the speed itself isn't a huge issue. I don't think I found an inn till the last minute of gameplay, so any damage you take you're gonna have to heal via magic or potions. If I can lobby another complaint, it'd be that, especially in relation to the garden maze, the first (And only!) dungeon in the game.
Once you enter, you can only exit by going through the whole thing. The door you came in through no longer works, and there isn't a good story reason for that. I hadn't monkeyed around too much outside of town so I had plenty of HP and MP and was able to manage my health situation till I got outside. It's conceivable though, that a player could become trapped and unable to fight their way through. You can also exit the dungeon without beating the boss and the game doesn't seem to care. Beating the boss does give you access to a treasure chest... that contains a potion, the same as basically every other chest. Even a "dangerous part" of the basement, containing the King's most cherished treasures, but so dangerous that the king won't enter contains... a potion. For all the hype the guard gives, it oughta be a little more exciting than that, yeah?
There seems to be some kind of crafting system for magic and equipment, rather than straight up buying. It's still shop based, so you'll trade 2 steel for a sword, and then a sword + magic for a magic sword. Some of it seems pretty complicated and I never had the means to craft any spells. In fact, the dojo master gave me a spell for free and insisted I teach it to the main character before fighting some other rube... but my regular attack did 42 damage as opposed to the fire spell's 12. Don't be afraid to keep the main character a physical guy and let the lady take care of all the magic, dude. No law says everybody's gotta be able to do everything.
The story's a little heavy-handed and there are some typos if that bothers you, but it's an interesting start at least and I'm left wondering where it's going to go. It's unusual to have a game where the protagonist is the one encouraging a peaceful solution with the monster of the week, and he seems at odds with the rest of humanity. Surely that's going to lead to some drama. It's a fine rookie effort, rough in spots, but the kind of thing that should polish itself out as it goes. The demo is shortish, so if you're feeling like a quick OHR RPG this wouldn't be a bad decision. Just don't expect too much.