Games like Spikit
Games like Spikit include Vampire Survivors, Enter the Gungeon, Cuphead, TouHou Makuka Sai ~ Fantastic Danmaku Festival Part II, and Bit Blaster XL. We matched them by the tags players give Spikit on Steam (Indie, Casual, Bullet Hell, and Difficult): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Bullet Hell · Indie · Casual

Enter the Gungeon
Shared: Bullet Hell · Indie · Difficult

Cuphead
Shared: Difficult · Indie · Bullet Hell

TouHou Makuka Sai ~ Fantastic Danmaku Festival Part II
Shared: Indie · Bullet Hell · Difficult

Bit Blaster XL
Shared: Bullet Hell · Difficult · Casual

TouHou Makuka Sai ~ Fantastic Danmaku Festival
Shared: Indie · Bullet Hell · Casual

Hollow Knight: Silksong
Shared: Indie · Difficult

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

Touhou Tenkuushou ~ Hidden Star in Four Seasons.
Shared: Bullet Hell · Difficult · Indie

Timberman
Shared: Casual · Indie · Difficult

Nuclear Throne
Shared: Indie · Difficult · Bullet Hell

Just Shapes & Beats
Shared: Bullet Hell · Difficult · Indie

Getting Over It with Bennett Foddy
Shared: Difficult · Indie · Casual

Megabonk
Shared: Indie · Bullet Hell · Casual

Game Dev Tycoon
Shared: Indie · Casual · Difficult

Minimalism
Shared: Indie · Casual · Difficult

The Binding of Isaac: Rebirth
Shared: Indie · Difficult

Baba Is You
Shared: Indie · Difficult · Casual

Soundodger+
Shared: Indie · Casual · Bullet Hell

Zup! S
Shared: Casual · Indie · Difficult

Spin Rhythm XD
Shared: Casual · Indie · Difficult

Turbo Pug
Shared: Indie · Casual · Difficult

Super Hexagon
Shared: Indie · Difficult · Casual

Rabi-Ribi
Shared: Bullet Hell · Indie · Casual