Games like Hydra Slayer
Games like Hydra Slayer include Tales of Maj'Eyal, Sol Cesto, Into the Breach, Backpack Hero, and Shattered Pixel Dungeon. We matched them by the tags players give Hydra Slayer on Steam (Traditional Roguelike, Puzzle, Education, Inventory Management, and Mythology): closest matches first, and among equally close ones the better-known games.

Tales of Maj'Eyal
Shared: Traditional Roguelike · Turn-Based · Procedural Generation

Sol Cesto
Shared: Puzzle · Dungeon Crawler · Procedural Generation

Into the Breach
Shared: Puzzle · Strategy · Turn-Based

Backpack Hero
Shared: Inventory Management · Turn-Based · Strategy

Shattered Pixel Dungeon
Shared: Traditional Roguelike · Turn-Based · Dungeon Crawler

Caves of Qud
Shared: Traditional Roguelike · Procedural Generation · Turn-Based

ADOM (Ancient Domains Of Mystery)
Shared: Traditional Roguelike · Turn-Based · Dungeon Crawler

Dungeons of Dredmor
Shared: Traditional Roguelike · Turn-Based · Dungeon Crawler

Dungeonmans
Shared: Traditional Roguelike · Turn-Based · Strategy

Jupiter Hell
Shared: Traditional Roguelike · Turn-Based · Strategy

Desktop Dungeons
Shared: Puzzle · Turn-Based · Fantasy

Rogue Fable III
Shared: Traditional Roguelike · Turn-Based · Strategy

One Way Heroics
Shared: Traditional Roguelike · Turn-Based · Dungeon Crawler

Lootbound
Shared: Inventory Management · Strategy · Pixel Graphics

Sproggiwood
Shared: Traditional Roguelike · Turn-Based · Procedural Generation

Cogmind
Shared: Traditional Roguelike · Turn-Based · Strategy

Elin
Shared: Traditional Roguelike · Pixel Graphics · RPG

Niche - a genetics survival game
Shared: Puzzle · Education · Turn-Based

Tangledeep
Shared: Traditional Roguelike · Turn-Based · Dungeon Crawler

Slipways
Shared: Puzzle · Strategy · Turn-Based

Rogue
Shared: Traditional Roguelike · Procedural Generation · Fantasy

MidBoss
Shared: Traditional Roguelike · Turn-Based · Procedural Generation

The Doors of Trithius
Shared: Traditional Roguelike · Procedural Generation · Turn-Based

Tactical Breach Wizards
Shared: Puzzle · Turn-Based · Turn-Based Tactics

