Games like Fireboy & Watergirl: Elements
Games like Fireboy & Watergirl: Elements include It Takes Two, PICO PARK, Human Fall Flat, Broforce, and Cuphead. We matched them by the tags players give Fireboy & Watergirl: Elements on Steam (Action, Local Multiplayer, Multiplayer, Puzzle Platformer, and Nostalgia): closest matches first, and among equally close ones the better-known games.

It Takes Two
Shared: Multiplayer · Co-op · Local Co-Op

PICO PARK
Shared: Multiplayer · Co-op · Puzzle Platformer

Human Fall Flat
Shared: Co-op · Multiplayer · Action

Broforce
Shared: Action · Co-op · Multiplayer

Cuphead
Shared: Co-op · Multiplayer · Local Co-Op

BattleBlock Theater®
Shared: Co-op · Multiplayer · Local Co-Op

ibb & obb
Shared: Co-op · Local Co-Op · Multiplayer

Castle Crashers®
Shared: Co-op · 2D · Multiplayer

BADLAND: Game of the Year Edition
Shared: Action · Multiplayer · Indie

Overcooked! 2
Shared: Multiplayer · Co-op · Local Co-Op

Gang Beasts
Shared: Multiplayer · Action · Co-op

Move or Die
Shared: Multiplayer · Local Multiplayer · Action

Unravel Two
Shared: Multiplayer · Co-op · Action

Brawlhalla
Shared: Multiplayer · Local Multiplayer · Action

Awesomenauts
Shared: Multiplayer · Action · 2D

Stick Fight: The Game
Shared: Multiplayer · Local Multiplayer · Action

Duck Game
Shared: Multiplayer · Local Multiplayer · Action

Streets of Rage 4
Shared: Action · Local Multiplayer · 2D

Left 4 Dead 2
Shared: Co-op · Multiplayer · Action

Pikuniku
Shared: Multiplayer · Action · Indie

SpeedRunners
Shared: Multiplayer · Local Multiplayer · Action

Lara Croft and the Guardian of Light
Shared: Action · Co-op · Local Co-Op

PEAK
Shared: Multiplayer · Co-op · Adventure

PICO PARK 2
Shared: Multiplayer · Action · Co-op