Games like SPLEEN
Games like SPLEEN include A Dance of Fire and Ice, Rhythm Doctor, Timberman, Geometry Dash, and Shower With Your Dad Simulator 2015: Do You Still Shower With Your Dad. We matched them by the tags players give SPLEEN on Steam (Music, Casual, Funny, Action, and Indie): closest matches first, and among equally close ones the better-known games.

A Dance of Fire and Ice
Shared: Music · Indie · Singleplayer

Rhythm Doctor
Shared: Music · Indie · Action

Timberman
Shared: Casual · Indie · Action

Geometry Dash
Shared: Music · 2D · Singleplayer

Shower With Your Dad Simulator 2015: Do You Still Shower With Your Dad
Shared: Funny · Casual · Arcade

Muse Dash
Shared: Music · Casual · Singleplayer

Vampire Survivors
Shared: Indie · Casual · Singleplayer

DJMAX RESPECT V
Shared: Music · Casual · Action

AudioSurf
Shared: Music · Casual · Indie

pureya
Shared: Casual · Arcade · Funny

Super Hexagon
Shared: Indie · Arcade · Action

Music Racer
Shared: Music · Indie · Action

Retrowave
Shared: Casual · Indie · Music

WAVESHAPER
Shared: Casual · Action · Music

SUPER CHICKEN JUMPER
Shared: Arcade · Funny · 2D

Gang Beasts
Shared: Funny · Action · Casual

Spin Rhythm XD
Shared: Music · Casual · Indie

Sayonara Wild Hearts
Shared: Music · Action · Casual

Cat Goes Fishing
Shared: Funny · Casual · Indie

Melatonin
Shared: Indie · Music · Action

Pizza Tower
Shared: Indie · Funny · Action

There Is No Game: Wrong Dimension
Shared: Indie · Funny · Casual

Razortron 2000
Shared: Casual · Indie · Arcade

BARRIER X
Shared: Music · Indie · Action