Games like HAMMY
Games like HAMMY include ALTF4, Only Climb: Better Together, Toree 2, Pumpkin Jack, and Haste. We matched them by the tags players give HAMMY on Steam (Action, Casual, Indie, Arcade, and Platformer): closest matches first, and among equally close ones the better-known games.

ALTF4
Shared: Action · Runner · 3D Platformer

Only Climb: Better Together
Shared: 3D Platformer · Precision Platformer · Arcade

Toree 2
Shared: Action · 3D Platformer · Platformer

Pumpkin Jack
Shared: Action · Indie · 3D Platformer

Haste
Shared: Action · 3D Platformer · Runner

Downwell
Shared: Indie · Precision Platformer · Action

Rogue Legacy 2
Shared: Action · Arcade · Indie

Last Train Outta' Wormtown
Shared: Action · Platformer · 3D Platformer

Kao the Kangaroo: Round 2 (2003 re-release)
Shared: Action · Casual · 3D Platformer

Twin Shot Deluxe
Shared: Action · Casual · Arcade

Woodle Tree Adventures
Shared: Indie · Platformer · Action

Yooka-Laylee
Shared: Indie · 3D Platformer · Action

SONIC X SHADOW GENERATIONS
Shared: Action · 3D Platformer · Platformer

VHOLUME
Shared: Casual · 3D Platformer · Platformer

Neon White
Shared: Action · 3D Platformer · Platformer

Geometry Dash
Shared: Precision Platformer · Platformer · Indie

Kao the Kangaroo: Mystery of the Volcano (2005 re-release)
Shared: Action · Casual · Platformer

Lunistice
Shared: 3D Platformer · Platformer · Arcade

Toree 3D
Shared: Platformer · 3D Platformer · 3D

Crash Bandicoot™ 4: It’s About Time
Shared: Action · Platformer · 3D Platformer

Pikuniku
Shared: Indie · Casual · Action

A Dance of Fire and Ice
Shared: Indie · Arcade · Casual

Spyro™ Reignited Trilogy
Shared: Action · 3D Platformer · Platformer

Super Meat Boy Forever
Shared: Action · Indie · Platformer