Xinyue Feng
All work

02 · Terraria mod · In development

Other­worlds

Thirty-eight bosses from Hollow Knight, Hollow Knight: Silksong, Dead Cells, Cuphead and The Binding of Isaac come to Terraria with their signature moves. Each game arrives as its own pack of bosses, weapons and gear.

See the five packs
Role
Lead developer, with AI tools
Status
In development
Platform
Terraria (tModLoader), single player and multiplayer
Built with
C#; Claude Code, OpenAI Codex and AI image generation
In-game screenshot: the Devil, a grinning black figure with horns and a trident, on a red-and-gold throne in Terraria’s underworld
The Devil, the Cuphead pack’s final boss, on his throne in Terraria’s underworld.

What it is

The bosses fight with the moves they’re known for, and they’re spread across a whole playthrough, from the first days of a new world to beyond the Moon Lord. Their weapons and gear fit Terraria’s melee, ranged, magic and summoner classes.

38Boss fights
80+Weapons
5Game packs
2Languages

Summon any boss when you’re ready, then collect its treasure bag, trophy, mask and relic. Play alone or with friends, in English or Simplified Chinese.

The five packs

Hollow Knight

Strike with the nail, heal with Soul, cast spells and choose your charms. Thirteen bosses: the False Knight, Hornet (as Protector and as Sentinel), the Mantis Lords, the Broken Vessel, the Soul Master and Soul Tyrant, the Dung Defender, the Watcher Knights, the Traitor Lord, the Nightmare King Grimm, the Pure Vessel and the Absolute Radiance.

The Absolute Radiance, a pale winged moth-god inside a golden halo of spikes, above a valley
The Absolute Radiance, inside a halo of golden spikes.
The Pure Vessel, a slender white-masked knight, focusing inside a ring of light
The Pure Vessel focuses.

Hollow Knight: Silksong

Silksong’s crests, tools and abilities. Seven bosses: the Bell Beast, Lace, Nyleth, Trobbio, the First Sinner, Grand Mother Silk and the Bell Eater.

Grand Mother Silk, a towering pale figure, lunging at the player with needles in the air
Grand Mother Silk’s claw attack.

Dead Cells

Dead Cells-style weapons and skills. Seven bosses: Mama Tick, Conjunctivius, the Concierge, the Time Keeper, the Giant, the Hand of the King and the Queen.

Conjunctivius, a spiked purple eyeball creature, hanging from chains in the sky
Conjunctivius, still in its chains.
The Time Keeper, a white-haired warrior, lunging with a long blade in front of a clock face
The Time Keeper lunges.

Cuphead

Finger-gun shots, a dash, and the parry of anything pink. Nine bosses: the Root Pack, Goopy Le Grande, Cagney Carnation, Baroness Von Bon Bon, Captain Brineybeard, Grim Matchstick, Sally Stageplay, King Dice and the Devil.

The Devil’s giant red head with yellow eyes and fangs, filling the screen above small platforms
The Devil’s giant head, late in the fight.
Sally Stageplay with wings, flying across a theater set of clouds, a sun and a crescent moon
Sally Stageplay swoops in on a stage wire.

The Binding of Isaac

A trapdoor opens onto an otherworld of its own: a top-down basement in Isaac’s style, laid out fresh every run, with lit rooms, darkness between them and no gravity. Monstro and the Duke of Flies wait below, and beating them earns keepsakes you can use back up in Terraria.

A top-down stone basement room: Monstro, a big pink blob with a gaping grin, right beside the player
Monstro corners you in the basement.

Credits

Development led by Xinyue (Lily) Feng with AI tools: the code is written with Claude Code and OpenAI’s Codex, and the sprites are generated with AI image tools.

An unofficial fan project, to be released free; the games belong to Team Cherry, Motion Twin, StudioMDHR, Edmund McMillen and Re-Logic.