Games like Frak!
Games like Frak! include Sonic Mania, FEZ, Webbed, Pizza Tower, and Unpacking. We matched them by the tags players give Frak! on Steam (Casual, Retro, Puzzle, Pixel Graphics, and Platformer): closest matches first, and among equally close ones the better-known games.

Sonic Mania
Shared: Retro · Platformer · Pixel Graphics

FEZ
Shared: Puzzle · Platformer · Pixel Graphics

Webbed
Shared: Pixel Graphics · Platformer · Cute

Pizza Tower
Shared: Platformer · Cartoony · Pixel Graphics

Unpacking
Shared: Casual · Pixel Graphics · Puzzle

Sonic Origins
Shared: Retro · Pixel Graphics · Casual

Out There Somewhere
Shared: Pixel Graphics · Platformer · Puzzle

Purple Place - Classic Games
Shared: Casual · Retro · Puzzle

Celeste
Shared: Pixel Graphics · Platformer · Singleplayer

Baba Is You
Shared: Puzzle · Pixel Graphics · Singleplayer

Zuma Deluxe
Shared: Puzzle · Casual · 2D

Laughing to Die
Shared: Casual · Puzzle · Platformer

KarmaZoo
Shared: Casual · Puzzle · Platformer

Portal 2
Shared: Puzzle · Platformer · Singleplayer

Is This Seat Taken?
Shared: Casual · Puzzle · Singleplayer

The Messenger
Shared: Retro · Platformer · Pixel Graphics

Defy Gravity Extended
Shared: Puzzle · Platformer · Casual

Papers, Please
Shared: Pixel Graphics · Singleplayer · Puzzle

Scribblenauts Unlimited
Shared: Casual · Puzzle · Singleplayer

Super Meat Boy
Shared: Platformer · Pixel Graphics · Singleplayer

ElecHead
Shared: Puzzle · Pixel Graphics · Platformer

Braid
Shared: Puzzle · Platformer · Singleplayer

Shovel Knight: Treasure Trove
Shared: Retro · Pixel Graphics · Platformer

Moonleap
Shared: Puzzle · Pixel Graphics · Platformer