Your analysis of the wording raises another interesting point. It's not even clear that an investor is part of the SatoshiSlot bankroll in the first place. However, the loss on this day and a look at the recent big wins makes it undoubtedly clear that the bankroll is shared by both games.
Bet on the House
You have the opportunity to be part of Satoshi Dice's bankroll. The bankroll is the total amount that that players have placed to bet on the house and you are paid according to your percentage of the house's bankroll. Satoshi Dice uses a 1.9% house edge and backers get 50% of the house wins or losses. This means a 0.95% Expected Value (EV) that is shared by the backers. Affiliate earnings, Leader Board rewards and other rewards are not paid by the backers, and there are no additional fees. Minimum amount to bet on the house is 0.001 and there is no upper limit.
Based on their terms and conditions, you invest only in Satoshi Dice. They offer Satoshi Dice and Satoshi Slot, but they speak only about the possibility to invest in Satoshi Dice and not one word about to invest in Satoshi Slot.
How much is the house edge for Satoshi Slot?
I mean they do not expect that anyone will initiate legal action, so they write any kind of not valid or uncomplete nonsense in the terms and conditions.
I think this site is going down the drain. All the claims of lost balances lately and their unwillingness to ever offer support. Even their cold storage has been depleted lately and only holds about 2/3 of current bankroll (ignoring customer balances that are not in the investment)
It does not matter if they have only 2/3 left. Only a few victims will claim and first come first serve.
1) "Welcome to Satoshi Dice - The Original and Best Bitcoin Betting Game"
-> this statement on their website confirms that they speak about the Satoshi Dice game and not about Satoshi Dice as the website operator
2) "Satoshidice.com is operating under the gaming licence 1668/JAZ"
-> this confirms that the website operator is satoshidice.com and not Satoshi Dice