Terraria: Otherworld, the sequel to popular sandbox exploration title Terraria, has a heavy tower defence component.

The game’s overall goal is to rid the world of Corruption, and the primary method of doing so will be by finding or crafting and then activating things called Purifying Towers.

“These machines of ancient design will push back anything unnatural in the world,” said developer Re-Logic.

Purifying Towers need to be defended by customisable Wartowers so the player can ward off the advances of the evil forces without having to be physically present.

Though the game includes a core story line, Re-Logic emphasised that free exploration is a key element.

“We want to stress the fact that though this is a more structured approach, we are absolutely trying to retain as much player freedom as possible,” it said.

“In order to build upon Terraria’s very high replay value, the story will not be a fixed narrative – but rather a dynamic mix of key story elements that are used to create a fresh play through every time a player replays the game.

“We are striving to give the player as unique a story experience as possible with each and every playthrough.”

Although it's a standalone game, Terraria: Otherworld is "a novel take on the Terraria experience” set in an alternate dimension of the first game's universe rather than a direct sequel.

Terraria: Otherworld is in development for PC, but new-gen console versions are under consideration as well.

"Our goal is to have Terraria: Otherworld available – as a full game – in 2015," said Re-Logic. "We will absolutely not be participating in an Early Access program."