I'm going to second the comments about the deadliness of Ars combat, and add:
ArM rules do not play well with multiple combats in a short amount of time. Every combat, there's a likely build up of fatigue, plus wound penalties which won't go away unless the group has lots of vis and time to sit around doing ritual spells.
So, unlike the standard RPG dungeon crawl where, after the first combat, you're only down 25% of hit points, no biggie for the next round of whatever, after a combat with any non-trivial adversary group, you should expect that your fighters will have at penalties to all rolls for the rest of the dungeon crawl unless you stop for a multi-hour rest; if it's really a dungeon crawl to stop a summoning ritual, you won't. Every fight will be harder and harder after the first - this means that, if the party gets to a dragon or something at the end, you have to expect them to not be at their freshest when fighting the dragon; it'll be dramatic, but it also might be extraordinarily fatal.
And it's entirely likely that, in a relatively early combat, a grog or two will be wrecked. Not killed, necessarily, but suffering a couple Medium Wounds or a Heavy Wound and maybe some fatigue, which means that said grog is useless for the rest of the adventure.
On another note, you asked about puzzles and traps. One kind of "standard dungeon RPG" puzzle is something where the characters have to do something clever (throw a switch in another room, figure out a passphrase, touch a hidden button) to open a door. Don't do this and expect the players to play that game. Someone will have Obliteration of the Metallic Barrier, Curse of the Rotted Wood, or sufficient Arts to simulate their effects (or merely Rego Terram to carve out a hole in the wall next to the door), and anything you do to stymie the use of those spells is going to be seen as unfair and your players will have less fun for it. Now, players do enjoy feeling like they were clever, so you can make a door with a ridiculously elaborate puzzle on it, and someone just destroys the door, and everyone cheers like when Indiana Jones shot the guy with the twirling sword.
"Traps" that I have used that players found fair:
- Rooms enchanted with persistent PeIg spells; for special challenge, you could have a room that merely has a persistent PeIm spell for sound
- PeTe spells cast on rings carved/inset in doorways - you only miss seeing one of those once
- A hallway with a colonnade where massive, dangerous lightning bolts arced randomly between the columns (this one incapacitated two characters, but I did make it clear that they were lightning bolts and they were running through them, so no one was put out by it)