Tales of Justice
Most of the Superpowers in the book are easy enough to understand if someone is familiar enough with comic books to play this game in the first place. Plant Growth makes plants grow at unrealistic speeds, and in odd places, at the will of the power user. Microscopic Vision lets the power user see things that are tiny. Glue makes something sticky.
Then there are the Superpowers that take a little bit of explanation. Their description might do complicated things to the basic rules of the game. Their names might be too vague, or misleading. Math might be required. Maybe it’s problematic to figure out the difference, in terms of actual effect, between one power and another.