Games like TetherGeist
Games like TetherGeist include Celeste, SANABI, Hollow Knight: Silksong, Jump King, and Super Meat Boy. We matched them by the tags players give TetherGeist on Steam (Action, Difficult, Precision Platformer, Adventure, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Difficult · Precision Platformer · Pixel Graphics

SANABI
Shared: Action · Pixel Graphics · Adventure

Hollow Knight: Silksong
Shared: Difficult · Indie · Adventure

Jump King
Shared: Difficult · Precision Platformer · Pixel Graphics

Super Meat Boy
Shared: Precision Platformer · Difficult · Indie

Hollow Knight
Shared: Difficult · Indie · Adventure

Rain World
Shared: Difficult · Pixel Graphics · Indie

Momodora: Reverie Under The Moonlight
Shared: Pixel Graphics · Difficult · Female Protagonist

Skul: The Hero Slayer
Shared: Action · Indie · Pixel Graphics

VVVVVV
Shared: Precision Platformer · Pixel Graphics · Difficult

Hyper Light Drifter
Shared: Pixel Graphics · Difficult · Action

Tomb Raider Game of the Year
Shared: Action · Adventure · Female Protagonist

Blasphemous 2
Shared: Difficult · Adventure · Pixel Graphics

Katana ZERO
Shared: Action · Pixel Graphics · Indie

Shovel Knight: Treasure Trove
Shared: Pixel Graphics · Action · Indie

Ori and the Will of the Wisps
Shared: Action · Adventure · Cute

Rise of the Tomb Raider™
Shared: Action · Adventure · Female Protagonist

Rabi-Ribi
Shared: Pixel Graphics · Female Protagonist · Cute

Downwell
Shared: Precision Platformer · Pixel Graphics · Action

OneShot
Shared: Pixel Graphics · Indie · Cute

The End Is Nigh
Shared: Precision Platformer · Difficult · Indie

Titan Souls
Shared: Difficult · Pixel Graphics · Action

Gato Roboto
Shared: Action · Indie · Adventure

Kitsune Tails
Shared: Precision Platformer · Difficult · Pixel Graphics