Ikana

The game seems pretty well optimized already imo. Unless you're running the game at max settings with a thousand block render distance I've noticed no frame rate issues

The game talks about there being something deep underground, but most of the time there really isnt anything there except some stronger drifters and old ruins. I think it would be cool if there was a new biome at the bottom of the world that would be big and open and full of strange new enemies and plant life. It would be like the hell biome in terraria when you dig to the bottom of the world. This would definitly require the bottom of the world height to be increased though, so you dont fall into it from the first cave you find. Much like the hell biome in terraria, this new biome would also stretch across the entire underground, making it very vast and more fun to explore because you wouldnt just be mining through rocks the whole time to reach a small pocket of the biome. This area would be very dangerous, and it would encourage the player to make steel armour to actually explore it. This can be where you find new blueprints in old remenents of civillization that have sunken to the bottom of the earth. These new blueprints could be recipes for a reusable bloomery or a faster way to smelt steel. Something that would incentivise the player to actually explore this place. The biome would be a big cavern with big mushrooms that glow blue that keep the cavern dimly lit, along with glow worms and other new plants that would light the place up. The ground would be covered in a moss or some type of plant that would almost seem like grass. The biome would look like the overworld but twisted. There would be completely new enemies that you can only find in this biome that would do lots of damage, making steel plate armour actually useful instead of just overkill against a pack of wolves. This is just an idea i had while playing the game. It could be genius and it'll get added in someway or this will just get buried in the forums. Either way I hope the devs at least look at this and consider adding something like this, as right now the game could certantly use more areas to explore