At the peak of accumulated bonuses, Item Collection Games outnumbered Building Credit Games.

These collectible games were born with Silicon Gaming, one of the first companies dedicated entirely to video slots. Launched in 1997, Silicon Gaming’s Odyssey Slots featured an elongated high-definition video display with icons to choose from among multiple games. Odyssey slots were the first with hard drives and had high-quality animation. The games were more like traditional three-reel slot games than other manufacturers’ bonus games

However, the accumulated bonuses were a feature that started with the initial launch of Odyssey, which included a game called Fort Knox.

In addition to three video reels, Fort Knox included a 10-digit code. During gameplay on the reels, you can collect code digits. There was no ability to collect the digits, nor were there options to do. It would simply collect digits at random. With each digit collected, you would be one step closer to cracking the code. When you had all ten digits, the screen changed to the animation of the vault door in Fort Knox. The door would open to reveal all the gold and a credit amount for your bonus payment.

In a short time, players learned to search for machines where the code had been partially solved by other players. If a game was available with five or more digits already solved, players had an advantage. At that point, those who play for profit would play the game until they opened the vault, then would go away and let someone else solve the first digits. Silicon Gaming produced several of these deposit bonus games.

Other game creators also produced accumulated bonus games. International Game Technology took that route with its Vision series, which put a bonus screen on the top reel of mechanical reel slots. A game in the Vision series was called Racing 7s. Three 7s – one red, one white, and one blue – wire on a segmented track. Every 7th had a credit amount associated with winning the race. In the highest-paid version, the red seven could earn 100 credits, the blue could earn 25, and the white could earn 10. Every time a seven landed on the main game payline, the 7 of the same color would go up one notch track. When his turn brought a 7 to the finish line, he won the award for 7 of the accused color. The trick was to search for machines with seven within two notches of the finish.

In short, you will rarely find bonus games accumulated today in casinos. When you do, choose machines where other players have taken you at least halfway to complete the requirements collection. In online casinos, there are progressive jackpots.