Hello everyone! I am a Spanish fan of the game and I have a few ideas that I think you would look good (Some more than others).
First, sorry for my poor English (I sometimes use a translator and can you read something strange: P)
-Tileset dwarven city: Diagonal floor and water brown is very rare.
-Aquatic Creature: In some stages, some creature that only boxes to move through water.
-Water + Electricity = Damage: When you use an electric wand against someone in the water should do more damage.
-Columns: In large rooms could have columns to hide from view or just to annoy
-Jammed Doors: They are not locked, but you have to hit them several times to be open (Making noise and alerting the enemies of the room you are going to open)
-Potion Blast: Damage, fire, smoke, destruction, and collapse of some boxes, use with caution.
-Collapses: Use the object 'Shovel' to clear a corridor of rubble and get going. Can give access to a lounge with Skeleton (undead) of some adventurer and an object.
-Shops: More variety would be better, and include rings and wands, even better.
-Shops: The merchant can identify objects without having to buy scrolls of identify, but paying of course
-Prisoner: A locked room in which an intelligent creature has an unfortunate adventurer prisoner. Protect him to a shop or the stairs from level 1 to win quite a lot of experience.
-Prisoner: A locked room in which an intelligent creature has an unfortunate adventurer prisoner. Protect him to a shop or the stairs from level 1 to win quite a lot of experience.
-List of potions and scrolls identified: Sometimes you play a lot, or leave the game for a while, and when you find a potion without identifying you doubt if the liquid fire, toxic gas or paralysis were known. A place where you tell the potions and scrolls left to know so you know what to expect would be fine for those who play for short periods of time or have little memory
-Intuition: A 50% unidentified potions or scrolls have an annotation indicating what could be. This fails 50% of the time anyway so it's not entirely reliable.
-An entry in green or red at the end of the description of weapons and armor bonus or malus indicating having more or less strenght than necessary
Brainstorm!!! I hope you like some ideas