Now this is a real dungeon crawl. Getting past traps, monsters and locked doors to the stairs is the whole game. Story, Cut scenes and character motivation are all minimal. Heck the textures, loot and sound effects are minimal too. Some may be bothered by that, But I wasn't.
I couldn't resist "old school mode", Break out the graph paper and DIY, Even for the first time out. Doing so, Mapping became the central focus of the game. The ambiance of the dungeon also became more pronounced as you don't want to get caught with a pencil in your hand and not a sword. I've played the old Wizardry and Bard's Tales and have always enjoyed the act of mapping. And I enjoyed it here as well.
Combat is real-time. So click on your weapon to attack or click on your hands to ready a spell, then select the rune pattern of the spell and then cast the spell. That's a lot to do for a mage, But then again, Casting spells should be more involved than swinging a sword. Turn-based would have been more “old school”, But may have lessened the importance of the ambiance as a result. The “Prepare, Attack, Move, Repeat” pattern is acceptable.
I found less than 50 secrets. I didn't try that hard as such things have never been a strong motivator for me in-and-of themselves. Getting through the dungeon had some tough spots. The worst of which was having to redraw a badly drawn map followed by some investigation/experimentation. The best of which was being thrown in a room full of nasties with my escape route closed off. Only option...run deeper into the dungeon. But you don't have time to map when your frantically running away.
For my party I decided to go sub-optimal and let a RNG choose my races, classes, initial attribute point allocations, traits (I did select a couple of racial traits myself) and pictures. I got 2 Minotaurs (A fighter and a mage) and 2 Insectoids (Both mages). Happily they all made it out alive. I'd be interested in taking another group of random criminals into the mountain.