Serra Ascendant turns a single mana into a massive lifelinking threat, which is why it still shows up in many of the best commander staples lists for white decks
That helps the accessibility, but I think the game came out, to some extent, a little more difficult than we wanted it to be
It relies on combos and timing when to play your cards, with several of the included characters triggering their effects upon entering or leaving the play area
For example, a colorless creature that enters the battlefield under your control with one +1/+1 counter on it won't receive an additional +1/+1 counter
Bonus Round is a new staple in Mizzix of the Izmagnus, Melek, Izzet Paragon, Zada, Hedron Grinder, Shu Yun, the Silent Tempest, Adeliz, the Cinder Wind, literally any Red Spellslinger deck