At what point would a puzzle with monetary prizes become gambling?

This is just a theoretical question I've been thinking about (I'm not doing this, and If I was I'd get a lawyer). Imagine you had some non-free video game, and sprinkled in the game were easter egg puzzles where, upon being the first to solve, you'd win money. At what point would this be considered a lottery?

The law states that in order for something to be gambling, we need three things: Prize (reward), Chance (randomness), and Consideration (payment to entry). My question is what qualifies as chance? If you had an easter egg that was 90% logic and 10% rng, does that count as chance? I'm curious if anyone knows this.