Games like Picnic Syndrome
Games like Picnic Syndrome include Firework, The Room Two, Please, Don’t Touch Anything, The Room, and Papers, Please. We matched them by the tags players give Picnic Syndrome on Steam (Hidden Object, Strategy, Puzzle, Visual Novel, and Time Manipulation): closest matches first, and among equally close ones the better-known games.

Firework
Shared: Puzzle · Horror · 2D

The Room Two
Shared: Puzzle · Hidden Object · Horror

Please, Don’t Touch Anything
Shared: Puzzle · Indie · Point & Click

The Room
Shared: Puzzle · Hidden Object · Point & Click

Papers, Please
Shared: Puzzle · Indie · Point & Click

The Room Three
Shared: Puzzle · Hidden Object · Point & Click

Rusty Lake Paradise
Shared: Puzzle · Point & Click · Horror

Frankenstein: Master of Death
Shared: Hidden Object · Puzzle · Point & Click

Bendy and the Ink Machine
Shared: Puzzle · Horror · Strategy

Hidden Folks
Shared: Hidden Object · Puzzle · Indie

No Case Should Remain Unsolved
Shared: Puzzle · Visual Novel · Point & Click

The Room 4: Old Sins
Shared: Puzzle · Hidden Object · Point & Click

Tiny Bunny
Shared: Visual Novel · Horror · 2D

SIMULACRA
Shared: Horror · Visual Novel · Point & Click

Slay the Princess — The Pristine Cut
Shared: Visual Novel · Horror · Choices Matter

Death and Taxes
Shared: Strategy · Puzzle · Choices Matter

Zero Escape: The Nonary Games
Shared: Visual Novel · Puzzle · Choices Matter

Inscryption
Shared: Puzzle · Horror · Strategy

Fran Bow
Shared: Puzzle · Horror · Point & Click

Milk outside a bag of milk outside a bag of milk
Shared: Visual Novel · Indie · 2D

Morphopolis
Shared: Hidden Object · Puzzle · Indie

Homicipher
Shared: Visual Novel · Horror · Text-Based

Rusty Lake: Roots
Shared: Puzzle · Point & Click · Horror

Buckshot Roulette
Shared: Strategy · Horror · Puzzle