If an effect refers to a card, spell, or permanent that has an Adventure, it won't find an instant or sorcery spell on the stack that's been cast as an Adventure
Eventually Wizards would print cards like Sphere of Resistance and Thalia, Guardian of Thraben that are cheap enough to be effective
Also, Kess is a strong competitive combo enabler that synergizes with cards like rituals or tutors, provided you use its ability on your turns
The other starter deck, the Rise of the Floodborn Amethyst and Steel starter deck includes a lot of Merlin and Madam Mim cards, but it's a real shame that it's not an all-in theme deck with a foil Madam Mim as well
However, that comes with two disclaimers
We will probably get to a small definition in a few lines of text, if I know myself But before that, just a bit about my feelings for prison decks