Mostly linear overarching structure (some optional hidden rooms, can get to level/floor 2 before beating the first boss and the final boss isn't located on the final floor?)
​​Pay to save or let the game auto-save at certain points
Consumable teleportation items (black onyx - teleport to the next dungeon floor, fire crystal - teleport backwards one floor) and some "same floor" teleporters within the dungeon
Some ability/tool gating (mattock lets you break brick blocks diagonally below or straight below you, a mantle (consumable) that allows to pass through most walls for a short time, hourglass consumable - lets you stun enemies and stand on them though the latter is never used to progress, winged boots consumable - time limited flight (alternate way of getting out of traps and into one of the towers), temporary and permanent stat boost items)
Dark rooms which can be lit with lamps
An elixir lets you revive where you died (like Fairies in Zelda)
Spectacles let you read an enemy’s stats and inventory
Invisibility rings (Demon's Ring, temporary consumable)
​Basic karma system (a bit weird and unintuitive, need to keep it low to enter the final dungeon and get the dragon slayer sword as well as to enter temples in which you can level up, can lower it with poison but these items are limited)
Level gating (have to reach a certain level to get to the next dungeon floor)
​​Can escape from battles
Which side you're attacked from matters
Limited enemies per dungeon
Hunger mechanic 
Shows enemy HP and your damage output

Xanadu Scenario II: Resurrection of the Dragon
Plays like an expansion pack and is non-linear in structure (can explore any of the 11 dungeons however you'll get crushed if you start with the later ones)
Can sell back items here
Weight mechanic (effectively limiting the amount of items you can carry)

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​Playthrough (MSX) - CRPG Addict Review