Games like Dark Old Sun II: Unspace
Games like Dark Old Sun II: Unspace include Black Myth: Wukong, Halls of Torment, Soulstone Survivors, The Ascent, and Warframe. We matched them by the tags players give Dark Old Sun II: Unspace on Steam (Action, RPG, Action RPG, Shooter, and Bullet Hell): closest matches first, and among equally close ones the better-known games.

Black Myth: Wukong
Shared: Action · Action RPG · RPG

Halls of Torment
Shared: Bullet Hell · Roguelite · Action

Soulstone Survivors
Shared: Action RPG · Bullet Hell · Roguelite

The Ascent
Shared: RPG · Action · Top-Down Shooter

Warframe
Shared: Action RPG · Action · RPG

Death Must Die
Shared: RPG · Bullet Hell · Roguelite

Hades II
Shared: Action · Roguelite · RPG

Last Epoch
Shared: Action RPG · RPG · Action

Vampire Survivors
Shared: Bullet Hell · Roguelite · Action

Goobies
Shared: Bullet Hell · Top-Down Shooter · Action

Yet Another Zombie Survivors
Shared: Roguelite · Top-Down Shooter · Action RPG

BALL x PIT
Shared: Action · Roguelite · Bullet Hell

Deep Rock Galactic: Survivor
Shared: Bullet Hell · Roguelite · Top-Down Shooter

Wolcen: Lords of Mayhem
Shared: Action RPG · RPG · Action

Hero Siege
Shared: Action RPG · RPG · Action

Hades
Shared: Action · Roguelite · RPG

Borderlands 2
Shared: Action · Shooter · RPG

Mass Effect™ Legendary Edition
Shared: RPG · Action · Action RPG

Army of Ruin
Shared: Bullet Hell · Shooter · Top-Down Shooter

SYNTHETIK: Legion Rising
Shared: Action · Roguelite · Top-Down Shooter

Nordic Ashes: Survivors of Ragnarok
Shared: Bullet Hell · Action RPG · RPG

Heroes of Hammerwatch II
Shared: RPG · Action RPG · Action

Weird RPG
Shared: Action · RPG · Action RPG

Warhammer 40,000: Inquisitor - Martyr
Shared: Action RPG · RPG · Action