In this game your character can permanently gain power, even across game sessions.
Dragon Warrior
NES 1986@1798
Metroid
NES 1986@1271
Castlevania II: Simon's Quest
NES 1987@1690
Mega Man
NES 1987@167
Eye of the Beholder
DOS 1991@1154
Super Metroid
SNES 1994@115
Diablo
Windows 1996@636