Gameplay is worth a quick shot, though some notable problems I have with it keep it from being something great/long lasting.
- The mana growth/deck construction/card draw doesn't suit a 40 card deck (30 may have been better).
- The nature of requiring an enemy of opposite 'element/temperature' often causes luck to heavily affect a game. Even without losing, some games end up at a standstill because you and the AI both just draw ice or fire enemies, creating really uneven pacing.

As an open source project made for the Godot Game Jam though, this is awesome in its scope and as a point of reference. It even has a built in method for buying new cards and customizing your own deck.
So as a starting point to experiment with deck constructing/building games, this is an amazing resource.
Though untested it even has basic multiplayer built in (requiring host/port etc).

good

No bugs, easy to understand gameplay, has a playtime of like 10 minutes top. But great game tough.

Maybe add like special treatment items? Or prehaps Alchemy with it as an expansion?

Cool to play as a time waster, you could get sucked into playing this the first few times.