Other than the striated boxes for the different power/toughness, leveler cards act the same as other MTG creatures
Rip test is pretty self explanatory
This means that the card pool is slightly larger, and given the experimental digital-only mechanics it's slightly more unstable
Whats probably holding it back is that it firstly requires graveyards to have cards in them, and secondly that youll always get the worst option
Each Set Booster contains 12 Magic cards, 1 Art Card, and 1 token/ad card or card from The List (a special card from Magic's history or Universes Within card), with a combination of 14 card(s) of rarity Rare or higher and 37 Uncommon, 37 Common, and 1 Land cards
I ended up with a few different shells to explore this, but there ended up being two basic ones that seemed promising