Hydra Slayer Windows, Mac, Linux, DOS, Android game

Hydra Slayer currently (14.4) features:

• a unique (AFAICT) gameplay mechanics (although the main idea is based on old mathematical puzzles). To defeat a Hydra, you have to choose your attacks carefully, just bashing it with your "best" weapon is not likely to be a successful strategy. To win the big game, you have to choose your set of weapons wisely, and use your resources efficiently!
• a theme which mixes high fantasy and mathematics
• open source (compiles on Windows, Linux, MacOS), and also an Android version
• traditional roguelike ASCII graphics, or tiles/3D display via NotEye
• 5 player character races with very distinct tactics:
  • Humans - the simplest but versatile race
  • Elves - equipped with the unique Bow weapon, powerful when close to mushrooms
  • Nagas - slow, but able to deliver mighty ambidextrous attacks
  • Trolls - can carry lots of weapons, but no other items
  • Halfling Twins - control two characters instead of one
• 28 enemy types:
  • 10 basic types of elemental hydras (each of them has two special variations)
  • 8 types of special enemies
  • harmless mushrooms for strategic advantage
• 24 types of equipment (not counting material and size/power variations)
• 15 weapon materials:
  • 10 elements corresponding to basic hydra types
  • 4 gem types for non-elemental equipment
  • 1 mighty special material
• 18 types of non-equipment items:
  • 7 runes to be used on your enemies
  • 3 scrolls to be used on equipment
  • 8 potions to empower yourself
• 3 game geometries to choose before the start of game:
  • traditional 8-directional
  • 4-directional for laptop users
  • hex board
• 8 level topologies (including the Mobius strip and Klein bottle)
• 11 level generators
• 2 endings:
  • a small one for compatibility with the 7DRL version and for short challenge games
  • a big one for those who want more hydra slaying