Games like Atomic Picnic
Games like Atomic Picnic include Risk of Rain 2, Gunfire Reborn, Ravenswatch, ELDEN RING NIGHTREIGN, and Vampire Survivors. We matched them by the tags players give Atomic Picnic on Steam (Roguelike, Roguelite, Action Roguelike, Bullet Hell, and Online Co-Op): closest matches first, and among equally close ones the better-known games.

Risk of Rain 2
Shared: Action Roguelike · Roguelike · Third-Person Shooter

Gunfire Reborn
Shared: Roguelike · Roguelite · Online Co-Op

Ravenswatch
Shared: Roguelike · Action Roguelike · Online Co-Op

ELDEN RING NIGHTREIGN
Shared: Roguelike · Online Co-Op · Multiplayer

Vampire Survivors
Shared: Action Roguelike · Roguelite · Bullet Hell

The Spell Brigade
Shared: Roguelite · Online Co-Op · Bullet Hell

Megabonk
Shared: Roguelike · Action Roguelike · Roguelite

Crab Champions
Shared: Action Roguelike · Roguelike · Multiplayer

Brotato
Shared: Roguelike · Action Roguelike · Bullet Hell

Enter the Gungeon
Shared: Roguelike · Action Roguelike · Bullet Hell

Roboquest
Shared: Roguelite · Action Roguelike · Online Co-Op

HELLDIVERS™ 2
Shared: Online Co-Op · Third-Person Shooter · Multiplayer

Gatekeeper
Shared: Roguelike · Bullet Hell · Co-op

Returnal™
Shared: Roguelike · Bullet Hell · Action Roguelike

Streets of Rogue
Shared: Roguelite · Action Roguelike · Roguelike

LORT
Shared: Action Roguelike · Roguelite · Online Co-Op

Hades
Shared: Roguelite · Action Roguelike · Roguelike

Children of Morta
Shared: Roguelike · Action Roguelike · Online Co-Op

Abyssus
Shared: Roguelike · Roguelite · Online Co-Op

Soulstone Survivors
Shared: Roguelite · Action Roguelike · Roguelike

PUBG: BATTLEGROUNDS
Shared: Third-Person Shooter · Multiplayer · Online Co-Op

Nuclear Throne
Shared: Roguelike · Action Roguelike · Bullet Hell

Risk of Rain (2013)
Shared: Roguelike · Action Roguelike · Online Co-Op

SYNTHETIK: Legion Rising
Shared: Roguelite · Action Roguelike · Online Co-Op