Great great game!! I bought the 4-pack just over 5 dollars for me & my friends (totally worth it)!!!
Would like to give a quick summary/review about terraria so here it goes.
The Terraria's core structure
So You have to create a character, and enter a randomly-generated world (small/medium/large). There's a day/night cycle, which means you'll immediately be under siege by zombies and floating eyeballs as soon as the sun goes down, so your first order of business is to put your starting set of copper harvesting tools to work and construct a house (complete with a table, chair, and light source so the guide npc can enter). Once you have a place to keep you safe at night, the world is pretty much your oyster. You run across the earth's crust to find some entry points into the vast network of underground caverns below your feet. You'll have to mine, chop, kill zombies, and return home with some iron, tin, and buckets of loot sourced from wooden, golden and variety of other chests as well as from the materials from enemy, you will need that for crafting the accessories later. You have to construct layered workstations to forge your harvest into better weapons and gear(crafting is fun), you'll have to build more houses that will attract new NPCs, who will sell you exotic items or offer fresh haircuts and many more other accessories and stuff, you'll eventually no longer have to fear the night, and will cut through zombies like cotton candy. After all that done you can fight bosses do events, fishing quests and other things like explore shrines, making themed houses for npcs and the list goes on. The fact that there are over a thousand items in total is insane!

Btw anyone who's getting started with terraria I suggest you to check the official terraria wiki, everything you need to know about weapon crafting, accessories, class setups, events, bosses, biomes, guides, npcs, every single thing you will get to know there! I'll attach the link below if somebody is interested!
Terraria Wiki[terraria.gamepedia.com]

lastly, I highly recommend everyone should give it a try once, the ton of content which you are getting under 5 dollars is insane!