1) Choose your bet size and chance to win. The house always had a 1% edge, reflected in the payout. This edge is much lower than slot machines in Vegas.
2) Invest in the house. Every bet affected your bankroll based on your % invested relative to the total bankroll. The house edge was on your side.
The operators of the site, Deb and Doog, encouraged anyone trying to make money to invest. They argued the expected value was positive, even though high-rollers sometimes went on winning streaks.
Despite the warnings/statistics Doog produced and the fact that there was a +EV way to play (investing), players still got addicted to the dice game itself. The rolls resolved in a fraction of a second, so some players would go on a tear and bet 3-4 times a second. The minimum payout was 1% of the house bankroll, so single bets of several hundred bitcoin were possible.
Several high-rollers ("whales") played for 14-16 hours straight in a state of intense "flow", generally winning early on and losing everything by the end. Sometimes hundreds of thousands of dollars of bitcoin (1000+ btc) lost in a single session. Sometimes coins would come out of cold storage to continue playing. The site had a chatroom where even investors encouraged the player to stop before they were ruined, but the players would generally deny addiction and continue rolling.
After losing it all, some players described the experience they were having as a chemical rush- as if they had just taken a drug.
Even users who were invested and had made sizable profits from investing were not immune to the lure of the game. Several withdrew their invested bankroll just to "play around" and fell in the same inevitable fashion.