I got a little bit confused. Is it possible to deposit in different currencies at the same period? Like, for example, one time in BTC, next time in LTC? or with only one account it's not real?
I have not tried that out but am sure that is possible since the site accepts a deposit in all the currencies and you use the right addresses for each of the deposits, I guess that will display information about the portfolio in your balance display so is left for you to choose which of the currency you want to place your bet in.
Yes that is correct. ️Coinslotty supports multi-currency wallet, so it is possible to deposit multiple cryptocurrencies at the same time.

It is important to note that all deposits require a minimum amount. Attempting to deposit less than the minimum amount may result in funds being lost, according to their terms of service.
Please note that the minimal amount of deposit is: 0.0001 BTC / 0.001 BCH/ 0.01 LTC/ 1 DOGE/ 0.01 ETH/ 0.001 XPR/ 0.01 USDT (ERC20) Please do NOT attempt to deposit below the mentioned amounts, as the funds will not reach your player account and will become permanently lost.
https://www.coinslotty.com/terms-and-conditions