Siralim 2

Siralim 2 is an old-school monster-catching RPG with no real end in sight. You summon and customize hundreds of creatures to fight for you, battling through endless dungeons, finding rare treasure and pouring it into upgrading your castle, empowering creatures, crafting artifacts and learning new spells. Every dungeon is randomly generated, with its own randomized quests and events, so you never visit the same one twice.

There are over 600 unique creatures to capture and summon, each with traits that strongly shape its performance in battle, and a breeding system lets you pair two creatures to produce an egg whose offspring inherits their attributes, the best route to new creatures and a stronger party. Creatures equip Spell Gems drawn from more than 300 spells, each gem carrying randomly generated properties from a pool of 23, so one Fireball might cost health instead of mana while another casts automatically after an attack.

Artifacts add another deep layer, with the blacksmith and enchanter letting you forge, re-forge, brand and enchant equipment from over 800 crafting materials, and favorite creatures can even be turned into Nether Creatures to wield items no normal creature can. There is no level cap and no inventory limit; difficulty scales as high as you want, content is introduced at a steady pace, and some players have logged thousands of hours without seeing everything. The first Siralim game is not required to enjoy it.