Classic mode is the most common way you're likely to play most of the games available in crypto casinos. It's a straightforward version of the game where you place a bet and cash out before the game crashes. If you take the cashout before the crash, you'll win whatever is shown as the multiplier.
Trenball crash mode is less common. In Trenball, you have three betting options.
Red (game crashes before the 2x multiplier)
Green (the climb or trajectory goes above 2x)
Moon (you only win your bet if the multiplier is 10x).
For each outcome, you're paid set odds: red (1.98x), green (2x), and moon (10x).