It's sort of okay. Low-end okay. It looks pretty, but the storyline's just generic fantasy plot beats and it's doing nothing interesting with its characters. It's the kind of underwritten anime where you nod and say "aaaaaaaaaaah" when you learn it's based on a game.
Gran is a nice bloke. Lyria is a nice girl. Gran saves Lyria and gets life-bonded to her. From now on, they'll die if they ever leave each other. That's an attention-grabbing premise... but nothing noticeable comes from it and the anime mostly just forgets about it, especially when Gran has to be heroic with a sword. ("Sword = heroism" seems so deeply engrained in the show's genre assumptions that Gran will have to stick a sword in a monster even when his goal is to save it. That's in ep.12 and the bizarre thing is that this works.)
Incidentally, "Lyria" is pronounced "Ruria". This show has a distracting fondness for counterintuitive Romanisation, c.f. also Vyrn (Bii) and Eugen (Oigen).
There's a female soldier without much personality, called Katalina. There's a flying lizard called Vyrn that does nothing meaningful and exists entirely to be a cute-ish animal mascot character. There's a male pilot called Rackam who in fairness has a personality, although his plot significance plummets as soon as he stops being a colourful encounter character. (He's a middle-aged pilot. One thing I genuinely liked about this show was its unusually wide spread of character ages, including a number of older bearded blokes.) There's a slightly bratty but nice kid called Io.
That's the cast, but in practice you can ignore who's who. That almost never makes any difference for the plot, which is pushing indistinguishable person-shaped plot pegs through a framework of Fantasy Stuff Happens. Baddies do villainous things. We explore the world. Our heroes go shopping, avoid killing goblins and have too many conversations with a hobbit with an annoying voice actor. (Emiri Katou's been in the business for a good while, actually, but here she's having to talk quite slowly and she failed to overcome this and convince me of the character's realism. She just sounded like an actress doing a voice.) We see gigantic god monsters who rule the seas and get grumpy if people are Despoiling The Environment. (This I quite liked, though. SF/fantasy can be a good way of conveying messages while coming across as less heavy-handed than you'd have seemed in more realistic stories.)
(a) it's normal to be able to hit crossbow bolts from the air with your sword, even if you're some random bloke in the forest.
(b) Tiamat (ancient Babylon), Cagliostro (18th-century Italian adventurer and self-styled magician), Sturm and Drang (18th century German literary movement), Leviathan (the Old Testament), Bahamut (Islam), etc. are unremarkable names and there's nothing wrong with mushing them all together like this. Ahem.
I've seen it claimed that this anime is a sequel of Rage of Bahamut, but I didn't notice any signs of that (although admittedly I've always avoided Rage of Bahamut). They're both Cygames franchises, but I don't think you need foreknowledge of one to watch the other. I was fine, anyway.
There's one place where the show tries to be character-based. A gloating camp baddie tells Lyria something that she takes too much to heart, so everyone else has to come and save her with the power of friendship.
To be honest, the villains are the most colourful characters here. You'll want to feed them to pigs, but that's the job description for villains. They're also sufficiently camp and silly that they can overstay their welcome quite quickly as far as you're concerned... but, yeah, they're definitely villainous.
The show gets weaker still towards the end. Ep.12 is basically a parade of fan-favourite game characters, who are admittedly cool. Unfortunately this leaves very little room for the main characters. It's as if I'd missed an episode where all these people got introduced. After that, OVA ep.13 is a reboot of the show with a different game protagonist instead of Gran. Her name's Djeeta. The biggest missed opportunity there is that we still have Gran in the title sequence! This episode looks fine and I imagine I'd have slightly preferred a Djeeta show, but to be honest I lost interest and fast-forwarded through this episode. Finding myself doing that was the point where I realised I officially didn't care what happened in this show. Ep.13 is a bikini episode, for what it's worth. After that, ep.14 might be another Djeeta episode, but I'm not entirely sure because I fast-forwarded through that too. It has Halloween pumpkins.
Ep.12 suggests that there might be a Season 2, but it also suggests that Gran's party will gain even more members and so that individual characters will get even less focus than they got in Season 1. That doesn't sound encouraging to me. Watch this show if you fancy the idea of low-urgency but nicely animated fantasy adventure with flying piranhas... actually, on second thoughts, that's wrong. If you watch anime for the artwork, you might like this. If you watch for the story and characters, I don't think there's much point in hunting down this show unless you're a fan of the game. I didn't dislike it, though. It's moderately pleasant in a slice-of-life "all friends together" way. The cast don't get enough to do, but they seemed like nice people. However there's barely enough in the storyline to sustain even one watch-through and I can't imagine anyone keeping the episodes in case they might want to watch them a second time one day.