The system seems a bit rigged.

There's an event called Duel where you complete given objectives within a time limit (they say you compete against opponents in-game, but it's just bot matches). However, when a certain objective is set in the final round, the target value is either ridiculously high, impossible in the current state (like having 2000 dice and being unable to proceed with the event, but the dice target is set to 4000...), or the dice rolls are so messed up that you can't possibly reach the goal. Even if you complete a third of the objective, the bot is already 9/10ths of the way there. Also, there's the Trail enemy elimination event. After a certain point, you have to deal damage by spinning a roulette to break the wall protecting the chests occupied by enemies. In the final section (Grand Prize), if you spin with a high multiplier, you just keep getting DANGER! (no damage). Sigh... you'll know when you try it... Don't spend money. This genre's main purpose is to rig the game like this and suck money out of players...