Enemy Philosophy

[IntegratedQuantum]

I want players to feel safe in their home, but also I want them to be able to go and search for danger when they want it.

• The surface should be safe, even at night to allow the player to build stuff without getting annoyed by enemies attacking.
• Once an area or structure has been conquered by the player, it should be safe forever. However if the final boss wasn't defeated or there is still some creatures left when the players leaves, enemies may slowly respawn in the structure.
• Enemies can be exclusively found in structures, or summoned by the player in terraria-style invasions.
• Enemies that drop rare or useful stuff should never respawn to encourage exploration over building mobfarms.
• Structures should be frequent around the world, multiple large structures should be visible at default render distance.
• Some enemies should be able to break and place blocks to reach the player. This could lead to some fun tower-defense invasions.
• Enemies should get harder when the player progresses.

[archbirdplus]

You can implement a rogue-like difficulty curve, where enemies get exponentially harder when digging deeper. This keeps the endgame from stagnating.