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Who Wants to be a Millionaire Mystery Box

Big Time Gaming
RTP 96.36%
Play Big Time Gaming Slots
Reels 5
Paylines 243
Min bet size 0.10
Max bet size 40
RTP 96.5
Wild symbols Yes
Free spins Yes
Bonus No
Jackpot No

Who Wants to be a Millionaire Mystery Box Slot Review

The Who Wants to be a Millionaire Mystery Box slots game can be found at casinos using Big Time Gaming software. Big Time Gaming is one of the newer software developers in the online gaming market. Alongside many of the smaller casino software providers Big Time Gaming focus exclusively on Slot Games. The company was founded by two individuals who reportedly were involved in the early days of New Tech Media that (via various sales and takeovers) ended up being part of OpenBet. Big Time Gaming publish the slots house edge information of all their games as standard. As such we can say that the House Edge of Who Wants to be a Millionaire Mystery Box is 3.338%.

Who Wants to be a Millionaire Mystery Box is a 5 reel slots game that is 3 symbols high. Instead of using paylines you form winning combinations by landing matching symbols of 3 or more across adjacent reels.

Special Symbols

Wild – The Wild symbol is the “X2”, which will substitute for all symbols other than Scatters and will double any win that they help to form.

Scatters – The “Millionaire” symbols are Scatters. To trigger the game’s Free Spins feature you need to land 3 “Millionaire” symbols on a single spin. When you do so you will be granted 7 or more Free Spins.

Mystery Box – Mystery Box symbols can only appear on reels 2, 3 and 4. When they do appear they will open up t reveal the same symbol in each box, one that will be chosen at random.

Bonus Features

Free Spins – If you land 3, 4 or 5 “Millionaire” symbols you will be awarded with 7, 12 or 20 Free Spins respectively. During the feature, every time you land a “Millionaire” symbol you will move one step up the multiplier ladder that is only in action during the Free Spins. There are 12 runs on the ladder in total with the top rung being worth 50 times the bet. Each time you move up a rung you will be awarded 1 additional Free Spins, except on the 4th, 8th and 12th rung when you will be awarded 3 additional Spins.

Gamble – After each win you have the chance to gamble your winnings. Each time you do so you will either double what you have or you will lose what you have. You can repeat the process up to 5 times with each amount gambled being the total of the previous amount won.


What made the original Who Wants to be a Millionaire so good was that you had the chance to sit in the hot seat and answer questions, that came with lifelines, in an attempt to increase the number of Free Spins you were awarded. Removing that feature has all but killed this slot for me. You get the mystery box feature that is added to the title, you Free Spins and you get Wilds. You even get a lower house edge. But despite all of that I would still play the original before this because it actually had something to do with the quiz show it was named after. Whilst this is by no means a bad game and has features that look similar to the original and the quiz, without those questions I see this a massive step backwards.

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