Rule of Rose contains an additional side quest which involves searching for extra items to unlock weapons and costumes using Brown. If the player accidentally misses a single item, they will miss out on unlockable goodies.
Note that in order to find all Films, "Goat Sisters" must be done before "Mermaid Princess".
Value of the side quests
The only reward for doing each particular side quest is the reward eventually obtained (there is not some achievement or bonus if the player does all of them). As such, the Films and Records are rather pointless when you can easily watch the game's cutscenes and listen to the game's music online, as all they do is unlock things previously heard/seen.
However, if the idea of turning Jennifer into a rag doll or octopus sounds appealing, you may do the Broken Robots side quest and get the October Ticket.
Regarding weapons, the Stick of Justice (Coin sidequest) and Revolver (Perfume sidequest) aren't really worth it either because the weapons are so weak. However, the Rusty Sword/Knight Rapier is a rather cool weapon, as it's a strong and powerful sword, so doing the Knives sidequest is worth it. It can also make the rest of the game easier and add a little challenge because the player needs to kill 5 Imps. The sword will also carry over to the next playthrough (it will be located in the Rubbish Bin).
The Unlucky Clover Field
- Use Chocolate or Bacon to find Film 8/14 in First Class Guest Sector - right hallway.
- Bacon can be found by using Biscuit in Port Livestock Room (the room with the pig).
- Use Film 8/14 to find Film 9/14 in Room 11 (Amanda's room, where the Butterfly Case found.-Key required).
- Use Film 9/14 to find Film 10/14 in Men's Lavatory (Connected to 2nd Passenger Corridor-Behind the One-Leaf Clover Door).
- Use Film 10/14 to find Film 4/14 in Men's Lavatory (Connected to 3rd Passenger Corridor).
- Use Film 4/14 to find Film 5/14 in Smoking Room (Connected to 3rd Passenger Corridor).
- Use Candy to find Perfume (Spring) in Working Class Luggage.
- If you need Candy, you can use Clothespin to find several in the Cafeteria.
- Use Perfume (Spring) to find Perfume (Summer) in VIP Room.
- Use Perfume (Summer) to find Perfume (Fall) in Library.
- Use Scone to find Aries in Port Livestock Room (the room with the pig).
- A Sock can be used to find a Scone in the Sector 6 Maintenance Passage.
- Kill the Imp wielding Baron in the 3rd Passenger Corridor.
The Bird of Happiness
- Kill the Imp wielding Viscount in the 1st Passenger Corridor.
The Goat Sisters
- Use Aries to find Taurus in Pantry (Connected to Sector 12 Maintenance).
- Use Film 5/14 to find Film 1/14 in Freezing Compartment (Connected to the Sector 12 Maintenance).
- Kill the Imp wielding Earl in the Wheelhouse.
- Use Film 1/14 to find Film 2/14 in the Wheelhouse.
- Use Film 2/14 to find Film 3/14 in Engine 3 Maintenance (Connected to Sector 8 Cargo Bay).
- Use Film 3/14 to find Film 6/14 in Engine 4 Maintenance (Connected to Sector 8 Cargo Bay).
- Use Film 6/14 to find Film 13/14 in Sector 2 Maintenance (Connected to Sector 6 Maintenance).
- Kill the Imp wielding Marquis in Central Stairway A.
Rag Princess Sews
- Use Perfume (Fall) to find Perfume (Winter) in Dressing Room.
- Put all 4 Perfumes into the gift box and unlock the Secret Room to find the Revolver.
- Use Taurus to find Gemini in the Sick Room.
- Kill the Imp wielding Duke in the Sector 7 Cargo Bay (during the power outage).
- Put all 5 knives into the gift box and obtain the Rusty Sword (after the power outage). If the player is playing on a next playthrough, the player can put the Rusty Sword into the gift box to obtain the Knight Rapier (or else the Rusty Sword will not be accepted).
- Use Gemini to find Cancer in Sector 6 Maintenance (upper room from the lift).
- Use Biscuit/Chocolate to find a Broken Robot in Central Stairway B. (Brown must be near it to find it)
- Use Biscuit/Chocolate to find a Broken Robot in Central Stairway C.
- Use Biscuit/Chocolate to find a Broken Robot in Central Stairway D.
- Use Biscuit/Chocolate to find a Broken Robot in Sector 13 Lift.
- Use Candy to find the King Coin in the Upper Floor Sector 13 Lift.
- Use Film 13/14 to find Film 14/14 in the Cafeteria (Connected to 1st Passenger Corridor).
- Use the King Coin to find the Queen Coin in the Middle Class Luggage (briefcase room).
- Use Cancer to find Leo in Broom Closet.
- Use Leo to find Virgo in First Class Guest Sector.
- Use Virgo to find Libra in the Library.
- Use Libra to find Scorpio in Central Stairway B (near the Section 6 lift).
- Use Scorpio to find Sagittarius in Central Stairway D.
- Use Sagittarius to find Capricorn in Port Livestock Area.
- Use Capricorn to find Aquarius in Sewage Treatment Room (Connected to Generator Room).
- Use Aquarius to find Pisces in the VIP Room.
- Put both Coins in the gift box to obtain the Stick of Justice.
- Use Film 14/14 to find Film 7/14 in the Reception Room (Ground Floor).
- Use Film 7/14 to find Film 11/14 in Headmaster's Room (Ground Floor).
- Use Pisces to find Sunday in the Closet Room (Ground Floor).
- Use Sunday to find Monday in the Cafeteria (during night time).
- Use Film 11/14 to find Film 12/14 (during night time) in Martha's Room (Connected to the Kitchen).
- Use Monday to find Tuesday in the Classroom (during night time).
- Use Tuesday to find Wednesday in the Dormitory (during night time).
- Use Wednesday to find Thursday (during night time) in the Sick Bay (First Floor).
- Use Thursday to find Friday (during night time) in the Play Area (First Floor).
- Use Friday to find Saturday in the Sewing Room (during night time).
Once Upon a Time
- Get the October Ticket in the basement to unlock the Octopus costume.