Seaside, as the name implies, is a shipping facility located on the sea off the coast of an island.
The main features of the map are the three buildings, behind which are the player spawns, the shipping crate yard, and the control tower, which the boss spawns behind the staircase to.
Behind one of the buildings are dumpsters, which allow access to the roof when using the Power Punch, as well as ramps for players who jump off the foundation into the water.
The tower has a fence around it, which can be shot through, as well as two exits for Players and The Boss to come and go, as well as a staircase leading up to the second floor control room and the two exits to the balcony area.
The shipping yard is full of crates, none of which are open, and a few that are stacked on top of each other. These crates can be climbed onto with the use of the Power Punch, and offer players a height advantage at the cost of being seen easier.
Building 1, which is the building on the right, nearest to the wall, contains a 'U' shaped main room, as well as a bathroom inside of the only other room. A hole in the roof next to the exit to Player Spawn can be accessed by bosses utilizing their double jump, or any dash mobility they may have.
Building 2, the middle building, has the inside of an empty store front, with a few empty shelves in the back and a counter in the front. The only thing of note in the building is a lone watermelon on one of the back shelves that cannot be picked up.
Building 3, the last building nearest to the corner of the foundation at the water, has the inside of a restaurant. It features a kitchen with basic appliances, such as a stove and refrigerator, as well as another room which seems to be a storage room.