Most annoying is that the browser version resets progress on close (so I keep seeing the same achievements). Some other games have this issue (not all, so I don’t think it’s my setup). Also, sometimes on re-focus a key is stuck (I know that was an older lwjgl thing). EDIT: Also having rings not melting (but still giving the rune). Though I also wish it were easier to just merge rings/spells instead (or allow transmuting spells).
The drain magic spell should have some use against magic monsters (especially animated purely by magic, if it does I couldn’t tell). EDIT: similarly, the totem of haste could be temporarily disabled with slowness spell.
Item stacking (even 2-4 depending on the item), especially as you mentioned that you intend for users to save runes (maybe even have universal storage for runes in forges, or similar for all items at staircases… or non-combat-accessible backpack). Also have worn equipment not count towards inventory space (or at least make one of each for weapon+ring+spell+armor/shield free, or maybe have bound items do this if they don’t already+bound spells?). EDIT: Forgot to say, keys shouldn’t take up inventory.
Re-work how allies are displayed (perhaps allow the game to use native aspect ratio but have one pillar for allies and the other for enemies). I think that’d also help when seeing a door listed instead of an enemy.
Give a zzz-type icon next to doors of a room with a sleeping enemy (or even big enemies moving, any spawning etc with generic sound icon).
Said before, but would like to see more unicode use (even keeping it to non-color font). Block walls, ┇ or ║ for doors, something like ░ or ▓ could be used for various things (grass, gas, rubble, spell animations).