Tenderfoot Tactics is a TRPG about witchy goblins and elemental magic with a deterministic combat system and a richly simulated battlefield. Boil lakes, raise mountains, grow plants, drain rivers. Start fires you later regret.
Tenderfoot Tactics is set to come out in early 2020 but you can already find a free prologue on itch.io: https://sonofbadru.itch.io/tenderfoot-tactics
Steam Page: https://store.steampowered.com/app/1061610/Tenderfoot_Tactics/