I love games like Terraria and Motherload, where players have to dig down and find more and more advance ores. The goal in both games is to dig all the way down, get the best items using the best ores, and beat an end boss.
I was wondering if you guys have any ideas or have seen a spin on this? Without making it into an open world sandbox like Minecraft.
In particular, as a small indie developer, how could I create more gameplay without having to add new content like what the developers of Terraria are doing?