Terraria.
So.. a lots of people thinks this game is just a minecraft copy.. Theese people wrong, this is a 2D action-adventure single and multyplayer sandbox survival game developed by Re-Logic.

The game released in may 2011 and has since been released for various other platforms and devices.

The game avilable on steam for 10$
Link: http://store.steampowered.com/app/105600/Terraria

In the game the player starts with 3 default items. A copper shortsword to fight, A copper axe for woodcutting and A copper pickaxe to mine. Many resources, and ores can be found while mining or exploring the underground caves.

The player uses resources to craft new items and equipments at an appropriate crafting station for that recipe, he/she can fight against enemies with swords, bows, guns, magic spells, and other weapons.

The game have many different enemies in Terraria like slimes, zombies and demon eyes.

When the player start the game he is in normal mode but when he kills the Wall of Flesh the world is turn to hardmode. (Wall of Flesh is a boss what u can summon in the hell with a guide voodoo doll).

After the player killed the Wall of Flesh it will throw a Pwnhammer, with that u can destroy demon,crimson altars what will bless the world with more powerful ores like palladium/cobalt, mythril/orichalium and adamantite/titanium. The player in hardmode have to fight with harder enemies and have to find/make better weapons,equipments.
When the player get the best weapons and equipments he have to kill the lunatic cultist then the 4 pillars and the last boss in the game the moon lord.. After the player killed it he/she can make/get the best weapons and equipments in the game.