

King of Thieves is a game about stealing gems from dungeons, while also protecting your own dungeons from other thieves who want your gems. The values of your gems add up into your rank, which determines where you are in the leaderboards of your league. There are 6 leagues - wood league, stone league, bronze league, silver league, gold league, and the kings league - and your goal is to reach the top of your league in a period of 3 days. After 3 days, the league competition resets (you do not lose your gems or your rank), and the top 3 players move on to the next league. You can only create and join guilds when you get into the stone league.
If you want to raid a dungeon, you need keys. You start out with a maximum of ten, although the max can be upgraded with coins. You get another key around every 4 minutes - the speed of key restoration is also upgradeable. You use these keys on a dungeon's lock. Every dungeon starts with 4 (?) keyholes on a lock. Only one of the keyholes will actually unlock the door. The number of keyholes on a lock is upgradeable.
In a dungeon, you move automatically. You just have to jump. The only way to turn around is by wall jumping. It's very simple. What ISN'T simple is other people's trap placements. You want to make traps in such a way that the people attacking your dungeon have to make hairpin jumps that they'll probably fail multiple times. The end of a dungeon is where the creator placed their gem totem. If you complete a dungeon flawlessly, you'll receive some gold from the dungeon's gold stash, and you'll recover some of the keys you used to get in. If you complete a dungeon with only 3 stars (around 1-3 deaths), you'll get the same amount of gold as you would from a perfect run, but no keys. With two stars, you'll get less gold, and with one star, even less. Completing a dungeon with 3 stars will also grant you a chance to get one of the player's gems. It'll only pick from gems that are actually IN the totem, and it starts out with only a 50% chance of getting it. If your gem gets stolen from another player, you are able to get revenge to have a chance of retrieving it. There is an upgrade that lets you decrease the chance of other players getting your gems that comes later on in play.
There's also dungeon creation and gem management, but I'll let you play the game to figure that bit out.
tl;dr steal gems from people to level up while also protecting your own gems
The game is really fun. Trying to beat some players' dungeons is a challenge, but it's so satisfying when you manage to steal a gem from someone else.
I would make a guild, but since most people will be playing the game for the first time, and you can't join guilds in the wood league, I won't bother.