There is a huge menu of options when you press the S key but I don't have a clue what any of them do.
On the assumption that you've bought all the skills that may or may not unlock some extra options:
Quick Save - Quick Load
Select Character for Standing Pic - Quest List
Move to over world - Guard Card's collection (you can walk on a spot and if you have that card it'll light up and you can inspect to see what stat that card is giving + what bonus it gives at certain level)
Minimap On/Off - Sound in town On/Off
Trap sensing On/Off - Scavenging corpses On/Off
Recollection room - Walking speed
Combat cutin On/Off - Name change
Voice setting - Clear cache
And looking at the rest of hte options nothing really important are there so eh.
btw, for D menu
Set support skill (you can choose which chaaracter will use the skill and which skill to use when you hit W)
Check mail (like when the janitor call for the girl)
Phone background
Current status (H status included)