Games like Happenlance
Games like Happenlance include Human Fall Flat, Pogostuck: Rage With Your Friends, Jump King, Getting Over It with Bennett Foddy, and A Difficult Game About Climbing. We matched them by the tags players give Happenlance on Steam (Intentionally Awkward Controls, Psychological Horror, Precision Platformer, Puzzle Platformer, and Difficult): closest matches first, and among equally close ones the better-known games.

Human Fall Flat
Shared: Co-op · Funny · Puzzle Platformer

Pogostuck: Rage With Your Friends
Shared: Psychological Horror · Precision Platformer · Difficult

Jump King
Shared: Psychological Horror · Precision Platformer · Difficult

Getting Over It with Bennett Foddy
Shared: Psychological Horror · Difficult · Physics

A Difficult Game About Climbing
Shared: Psychological Horror · Difficult · Precision Platformer

Celeste
Shared: Precision Platformer · Difficult · Indie

Chained Together
Shared: Co-op · Puzzle Platformer · Adventure

Geometry Dash
Shared: Difficult · Precision Platformer · Psychological Horror

Cuphead
Shared: Difficult · Co-op · Hand-drawn

The Game of Sisyphus
Shared: Intentionally Awkward Controls · Psychological Horror · Difficult

Hand Simulator
Shared: Psychological Horror · Difficult · Funny

RV There Yet?
Shared: Co-op · Funny · Adventure

I wanna be the Creator
Shared: Precision Platformer · Difficult · Psychological Horror

Don't Starve Together
Shared: Co-op · Difficult · Adventure

Heavenly Bodies
Shared: Difficult · Physics · Precision Platformer

BOKURA
Shared: Psychological Horror · Co-op · Puzzle Platformer

Gorilla Tag
Shared: Psychological Horror · Funny · PvP

Biped
Shared: Co-op · Funny · Puzzle Platformer

Portal 2
Shared: Puzzle Platformer · Funny · Co-op

Super Meat Boy
Shared: Precision Platformer · Difficult · Indie

Lethal Company
Shared: Co-op · Psychological Horror · Funny

N++ (NPLUSPLUS)
Shared: Precision Platformer · Difficult · Puzzle Platformer

BattleBlock Theater®
Shared: Co-op · Funny · PvP

Peaks of Yore
Shared: Psychological Horror · Difficult · Physics