After the town undergoes lockdown, a fat man in a blue shirt will be in the area just outside the town's front gate. He will ask (in Japanese) to rescue a lady in the town. Take him into the town and locate the double doors next to the town fountain. With the fat man in blue in tow, you may now rescue a rather risque lady. Taking those two back to the Sanctuary will earn Abbey's second weapon.
Mary's 2nd Weapon
Once the town is under lockdown, head to the dungeon near the Sanctuary and go down to the floor where you (presumably) rescued a little girl by raising platforms earlier in the game. A woman in a brown dress will be wandering that floor; rescue her and you earn Mary's second weapon.
Rusty's Second Weapon
After rescueing the initial few villagers in the wilderness, use Rusty to inspect the back wall of the Sanctuary's main hall. This allows you to rescue Abbey. Later, after the town is under lockdown, head back down to the same dungeon area and you will find a woman in a purple dress and hat wandering one of the halls. Speak with her and continue to the jail area where Abbey was imprisoned earlier. One of the larger northern rooms (check your map) has a kid and a man. Speak with the man first and take him back to meet the woman. With the man and woman in tow, speak with the kid. Take all three back to the Sanctuary and you earn Rusty's second weapon, which does at least 1200 damage.
Unlock Hard Difficulty
Clear the game on Normal difficulty or unlock weapon inheritence.
Unlock Vampire Mode
Clear the game on any difficulty and with any outcome to unlock Vampire Mode. This new game puts the player in control of the vampire to prey on the villagers and to defeat the ISLA vampire hunters.
Unlock Weapon Inheritence
The second weapons for Rusty, Mary, and Abbey can be carried over to subsequent new games once the following conditions are met:
Clear the game on any difficulty to unlock Vampire Side.
Clear Vampire Side.
Clear ISLA Side on Normal difficulty.
Abbey's Second Weapon...