The Ship, officially named Hisa Maru, is a large freight vessel stranded in the middle of the ocean. It is where the events of Monstrum take place. Escaping the ship is the primary objective of the game, and can be accomplished via three different ways.
Although it appears to have been abandoned, the player will quickly realize that they are not alone.
Layout & Rooms
Certain sections of the ship have a randomly generated layout, and are different in each new game. The basic layout of the sections is the same however, and procedural generation only occurs within predetermined sections.
Also referred to as the 'Crew Decks' or 'Residential Area', this is where the now likely deceased crew lived. Items commonly found here are duct-tape, lighters, fire extinguishers, and fuses. The most common item in this area are smashables (ie; glasses, cups, and bottles).
| The Bridge|
The dysfunctional control room of the ship, and the only room that has 4 different doorway entrances/exits.
Typically, at least one mission item will be found here.
| Loading Area|
Unofficially named, this area is where the Life Raft can be found, as well as the crane required to move it. Several crates can be found here that the player may use to hide in. Glowsticks are also commonly found here. This area connects to the Bridge.
| Mess Hall|
A dining cafeteria with 2 different doorway entrances/exits. Notably, the tables here are considered the best places to hide in the game, because they are the only hiding spots that allow you to clearly see everything in the room.
| Recreational Area|
An entertainment lounge with 2 different doorway entrances/exits. Notably, this room has a functional television in it that, when activated (assuming the fuse-box for the area is powered), will emit a loud static noise that can be used to attract the attention of the monster.
| Security Room|
A watch room for the crew of the Hisa Maru. Notably this room contains a fuse-box that powers the electrical lights of Deck 7 and 8.
Located in the bowels of the ship, the Lower Decks consist of a total of four levels, and are much more expansive and maze like than the Upper Decks. Ruptured steam pipes are primarily encountered here, making it a volatile place to be explore.
| Cargo Hold|
A potentially lucrative area to find a myriad of items, particularly glowsticks. Be warned, however, that large clusters of the Hunter's egg sacs can be found here if it is the monster, and that this area also has no electricity-based lighting, making the player easier prey for the Fiend as they don't have the flickering lights as a warning to the Fiend's proximity anymore.
| The Engine Room|
A multi-layered area densely packed with machinery and small workshops. A phone system can be found here that, when powered, can be used to "control" the movement of the monster by luring it to another phone, or to trick the monster into breaking down the door to the Master Steam Control Valve.
| The Submarine Room|
Commonly referred to as the "sub bay", this area houses the Submarine, a possible escape route, and has 3 different doorway entrances/exits, but notably contains no items or hiding places (there was a row of lockers next to to sub, but were ultimately removed during an update). The nearby control station overlooks the room, which the player may access and use to their advantage. A moveable cart in the room can be pushed to block off one of the three doors at any given time, or one of the three vents in the room, which are used by the Hunter.
Also referred to as the 'Outer Deck', this is the outside area in-between the Upper and Lower Decks. Red lockers can be found in pairs along both sides of the entire length of the ship. Items do not spawn anywhere on the Main Deck.
Located towards the center of the ship, the Helipad has a working helicopter planted on it, which can be used as a possible escape route for the player. Also in the area are four chain-locked storage containers, one of which randomly houses the Refueling Equipment needed for the Helicopter.
Generic rooms make up the vast majority of randomly generated areas of Upper and Lower Decks, and can contain anywhere from 0 to 3 or more various items in each of them, as well as hiding places such as lockers, cabinets, beds, storage shelves, or tables. The rooms are labeled as "generic" because they are otherwise unremarkable, and can even appear multiple times in an area.
| Room C06|
A bedroom with four possible hiding spots (2 lockers, 1 bed, 1 table). Reportedly, on the top bunk bed here will never spawn items (unlike on other bunk beds).
| Room C07|
A small room containing two lockers. The fuse box in this room provides power to the electrical lighting on Decks 5 and 6. Note that the half shelf in this room is not a table or desk, and thus cannot be used as a hiding spot.
| Room C24|
A storage room with two lockers. Although a vent passes through this room, it does not appear to be a suitable exit for the Hunter.
| Room C35|
A bathroom containing two lockers. The toilet can be activated (flushed), but the noise it makes does not appear to attract monsters.
A small workshop with two cupboards. Can sometimes contain a mission item.
Another small workshop with two cupboards. Can sometimes contain a mission item.
The biggest of the generic rooms in the Lower Decks: This room is also a workshop and usually contains a valuable mission item like the bolt-cutters or the welding kit. It also contains two cupboards and two lockers making it a good choice to hide from a pursuing monster.
A slightly bigger workshop with two cupboards. Can sometimes contain a mission item like the chain spool or the sub battery.
The ship is riddled with many hazards and traps, most of which possess the ability to either stun or kill the player.
| Pit Traps|
Exclusively found on Deck 5 and 6, pit traps are unstable areas of the floor that will cause the player to trip if they run over them. They have no effect when walked on, and can be jumped over. Notably, the Brute and the Hunter can also trip on them.
| Security Cameras|
Found exclusively throughout the Upper Decks, security cameras can spot the player and set off an alarm, which will quickly draw the monster to your location.
Found primarily throughout the Lower Decks, ruptured steam pipes can spawn along the walls of a corridor. At looping intervals they will blast out pressurized jets of steam. If the player happens to run into the steam, they'll be stunned and knocked backwards. A direct blast from steam will kill the player.
Located throughout both the Upper and Lower Decks, vents do not present any direct danger to the player unless the Hunter is the monster, who primarily emerges from them when it is alerted to a loud noise.
- The name of the ship, Hisa Maru, is revealed in Note #11.
- According to Team Junkfish's Design Blog #07, 2 other traps were planned to be implemented into the game: the Tripwire Trap, and the Drop Trap.
- The ship's external appearance as seen in the ending cutscenes seems to be somewhat different than it is in-game. (for instance, there is no second outer deck below the Main Deck, or at least not one that is accessible or viewable from any angle).