Build Better Boxes

How Casino Slot design best practices could lead to better Loot Box design.

How Casino Slot design best practices could lead to better Loot Box design.


A lot has been discussed recently about Loot Boxes in Games -> see the WIKIPEDIA page of Loot Boxes for a very good overview ( Criticism almost always comes to the conclusion that the use of loot boxes (the mystery purchase of random stuff the player might not really want or need) is to be condemned because it tricks our brains to impulsive purchases of even more boxes, in the hope to finally get the asset wanted in the first place. Loot boxes are considered “gambling” and therefore “evil” by some (mostly indie-) game creators and players.

The combination of Loot Boxes and a marketplace that allows to add virtually any value to the asset, independent of the initial price, only depending on supply and demand, is highly capitalistic and usually benefits only the owner of the marketplace (and some very early players that managed to get a good share of assets right at the beginning of the availability of the goods traded). This (important) part of loot boxes could literally relate to the casino operator, who always has the house edge to his advantage.

Given, a game designer does not have any moral issues to think about the above stated analytically, it might make sense to explore some findings of actual casino games, namely slot games, to understand what players like, adjure or reject. The target audience might differ, but some of the below stated design principles are just generally accepted.

This article should also give an outlook on how to implement loot boxes with a higher morale code, just in case you want to avoid the dark side and still create a rewarding free-to-play game experience (and that is not necessarily a contradiction per se).


When looking at casino slot games, it makes sense to start simple and look at the core micro gaming loop which is basically a “scratch-ticket”. The player purchases the chance to get either nothing, part of his/her investment, exactly his/her investment, a (small) multiple of his/her investment or (not frequently but the possibility is there) a life-changing win. To ease the pain of not winning what the player wants, usually the player gets some nice pictures, too. Slots just increase the scratch frequency to allow additional statistical (mis-)conceptions.

With slot design, there are some key numbers that evolved through the history of games & my personal experience as slot game designer. (Also somehow related to the infamous Skinner Box experiments.)

If the win for the player is always above his/her initial investment, a frequency of 7-12 non-winning outcomes is accepted. If it is possible to gain less than invested at all, a frequency of average 1 in 3 games is accepted. If the win/gain to be expected is above 10 times the initial investment (aka “a win to remember”), 20-30 non-winning games are ok. But behold: if you tease an event with a “near miss” like - omg: you almost got a significant win! -  more than 12 times until the event actually happens, the teasing will be considered annoying & unbelievable. Wins in the range of 20 times the players investment ideally happen all 70-100 games. Wins that happen less frequent than one in 300-400 games should minimal pay an average of 50 times the initial investment. The frequency of life-changing wins is irrelevant. No player expects them to happen anyhow. Think lotto: the chance is one to many millions, usually depending on the numbers of contributing players.

How does this relate to loot box design ? Since the player does never get his initial investment back in cash, the value of the “rarity” of the asset must be understood and ranked & mutually agreed on by the player community. Ideally, even the individual player understands about the value on it’s own. The numbers basically work 1:1. In the beginning, each purchased box is valuable to the player, since he/she has to learn about the status of the goods got, rank them etc. The more boxes opened, the less likely it is that the assets are of initial value to the player and the more important it is to get game design in place that handles the experience.


Loot boxes could be comparable with kids soccer sticker trading behavior. The cards are cheap (ideally bought by their parents, so no actual/comparable value is attached to the purchase). This can easily be achieved if the game uses ingame currency to buy the boxes. The next step is the removal of a marketplace, it’s fees or at least remove the possibility to rank a personal player status depending on the items traded. Furthermore the assets have to lose their trading value once used within the game (or even erode if not used/traded in time). Kids that trade soccer stickers can no longer trade the stickers once they have been put down in the sticker collection.

For games, this would mean randomized items that have players crave for more are ok, if there is a clear goal (even if its far in the future - think Pokemon: “collect them all!”), if their prize can not rise unlimited (because items owned but not used loose value) and their initial purchase is not linked directly to real world money.

What use would the boxes then still bring to the game (& it’s creators income)?
Well, fun for the player to collect and trade, for the collection’s sake while the purchase of boxes with ingame currency could still be linked to real money via ingame purchases.

Given a marketplace is a either limited or not directly available by design, casino slot related probabilities can come in handy to create a more enjoyable player experience. E.g. One in three boxes needs to add some (limited) value to the player experience immediately to keep the player purchasing boxes. One in 20-30 boxes should give the player a significant (to remember)  benefit, and so on.


I hope this short reflection sparks some ideas and helps to make loot boxes more enjoyable for players and game developers alike.
Please let me know your thoughts in the comments or find mit at Twitter (@KHufAb) for more gaming/gambling related thoughts.

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