Terraria is a complex game with many layers and options; as such it is sometimes hard to know what one should do or how to further progress in the game. This guide is targeted towards people who have the basics covered by the starter guide down but who are looking for more direction in what to do.
When starting the intermediate mode of the game you should already have most of these items, and I'll be assuming that you have already acquired most, if not all of these:
- Silver Tier Equipment
- A Ranged Weapon
- Grappling Hook
- About 200 Health
- Optional cool items like: Hermes Boots, Cloud in a Bottle, Magic Mirror and more.
Having mostly Silver Armor is a good decision when dealing with challenges that come up in mid-tier play. The monsters do higher amounts of damage and use harder tactics so damage reduction is key in many encounters. Also, having a Silver Pickaxe will allow you to tunnel faster as well as do enough damage that you can continue to tunnel while lower level enemies (like zombies, demon eyes and bats) run into your pickaxe. A decent ranged weapon like a Silver Bow, Enchanted Boomerang, or a large supply of Shuriken can really help in boss fights as well as against dangerous enemies like Man Eaters who are hard to engage at close range. Once you get to the stone layer of the Underground then Grappling Hooks become necessary to be able to get around efficiently. 200 Health is a good benchmark of mid-tier play and the boss monster Eye of Cthulhu will begin spawning once the character reaches that level of health. The optional items are just nice perks that are very easy to find as you explore and open chests during regular play. None of them are necessary but all make your life much easier.
The Stone Layer of the Underground is the third layer of the Underground, after the Dirt and Rocky layers but before the Underworld. In the top half you will start to find large, open caverns with sporadic water, while in the bottom half you will find slightly smaller caverns with pools of lava. This is a good layer to explore while you are mid-tier for a couple of reasons. You can easily find large veins of metals like Copper, Iron and Silver as well as decent amounts of Gold Ore and Gemstones. If you're planning on upgrading your armour and equipment to Gold Tier than you will be spending considerable time here. Also, Gold Chests seem to spawn more frequently at this depth, ensuring better gear.
The Underground Jungle is a layer that is part of the Underworld but has mud floors instead of dirt and has a different selection of monsters that spawn. The Underground Jungle is much more dangerous than the regular Underground and the mobs that spawn there can be frustrating to deal with. The benefits of going here are the Jungle Shrines that carry loot that doesn't spawn anywhere else in the game, and it is the only place to find Jungle Spores and Stingers which are needed to craft some of the next couple levels of items. Sometimes it's also nice to have a more challenging fighting experience while tunneling, something that the Stone Layer doesn't really give.
The Corruption is a layer accessable from the surface of the world. It has purple grass and trees and very distinct music. The monsters of the Corruption are much more difficult than normal surface monsters and require some planning in assaulting for those who aren't used to fighting them. Also, the purple stone of the Corruption, Ebonstone, cannot be picked except with a Nightmare Pickaxe or better, making Chasms harder to explore than other biomes without some creative thinking. The benefits of going into the Corruption are mostly to acquire Shadow Orbs which are necessary to progress in the game.
These are some goals to work towards that will give you some direction while pushing you towards the later tiers of the game.
As soon as you start meeting the requirements at the top of the page, you should think about fighting the Eye of Cthulhu. He will start appearing when you get 200 Health anyways, or you could craft his summon item, the Suspicious Looking Eye. Not only does he drop a decent amount of Demonite Ore which is useful, but killing a boss unlocks the Dryad NPC who is essential if you want to start exploring the Corruption (she sells Purification Powder that turns Ebonstone into regular Stone). Just go to the Eye of Chthulhu page and follow the tactics there. After you have done this you'll be better prepared for fighting later bosses like the Eater of Worlds who you will need to beat to get Shadow Scales to craft items such as the Nightmare Pickaxe.
Shadow Orbs are found at the bottom of Chasms in the Corruption. Breaking them open gives you an item that's found no where else, they have a 50% chance of spawning a meteor crash in your world (a great thing if you need Meteorite) and the third one you break will summon the boss Eater of Worlds. The first Orb you break will always give you a musket, a great ranged weapon, and because of your possesion of a firearm the Arms Dealer NPC will spawn at your house. Breaking Orbs is an essential part of moving the game forward.
Obsidian is another thing you will want to get while in mid-tier. Having an Obsidian Skull allows you to stand on otherwise damaging terrain, such as meteorite, without harm. It is also a good upgrade for the Shackle, giving +2 defense instead of +1. Once you have a Nightmare Pickaxe, Obsidian Skulls are a decent means of income for buying things from merchants. Plus, making huge Obsidian generators out of ridiculous amounts of water pouring non-stop into the Underworld is great fun. When making underground resevoirs for this purpose keep in mind items such as the Flippers and Gills Potion.