Art by Daniel LjunggrenEach player starts the game with an emblem with "At the beginning or your upkeep, sacrifice a permanent".
FAQ:"That sounds awful!"
The entire cube is build around this mechanic, so it's really not as bad as it sounds. You should see it as an environment that forces new creative strategies rather than an environment that stops you from playing like you are used to.
"What if something triggers in my upkeep?"
If you have other upkeep triggers than the emblem you can stack them like you normally would. Active player's triggers go on the stack first, so if your opponent has a trigger in your upkeep it will resolve before you have to sacrifice a permanent.
"Can I Stifle the trigger?"
Yes!
"Why is The Ur-Dragon in here?"
You can pitch it to Force of Will-effects in any color or reanimate it.
"Does the cube use the companion errata for Lurrus
Yes, you have to pay 
to put it into hand. I know that some cubes use the original companion ruling, but not this one.
Tokens
This archetype is pretty straight forward really. Go wide and stay ahead of the emblem. If you can get it, it's not too hard to meet the requirements for Lurrus
Ramp
Get a ton of mana early. Beat your opponent with 5-drops when they only play 1- and 2-drops.
Goblins
You can simply make so many that the emblem doesn't matter that much. And once you establish a board you can always sacrifice lands to keep the pressure high. There are a lot of cards that care about the top of your deck.
Zombies
Reanimator
The reanimation targets might not seem super impressive, but most of the 5-drops can carry a game pretty hard.
Artifacts
You can get a lot of value from simply looping eggs.
Convoke
You don't need to keep lands in play if you can use your creatures to cast your spells.
Counters
Generally, the blue decks are pretty complicated to put together since they usually rely on playing with very few or even no lands for the majority of the game
Manaless Control
This is probably the trickiest strategy in the cube. It revolves around not playing a land on your first few turns and use "free" cards like Force of Will or even non-blue cards like Force of Despair or Pyrokenisis to not fall too far behind. When your hand feels strong enough you can start playing threats like Jace's Phantasm, Vantress Gargoyle to finish opponents, or simply go for a mill finish.
Dredge
You can play it both with or without mana sources.
Storm / Eggs
Spend the first few turns on simply building up mana and sculpt your hand. Remember that you don't need to play a land on turn one, it might be best to just suspend your Lotus Bloom and wait.