Mental Slot Review

Slot Provider: Nolimit City

RTP: 96.08% | Variance: High | Maximum Win: 66,666x

Our Score: 9.0

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About Mental

Reviewed by:

Published Date: 19th November 2021

How We Review Slot Games

We test and rate all slot games across 5 criteria, assigning a score out of 10 for each and an overall score that is an average of the 5. To build an accurate assessment of each game we gather information from the supplier and play in real play or demo mode. Find out more.

Some days it feels like online slots are just getting bigger and badder all the time, driven by more exciting themes and game engines as each studio looks to outdo their rivals with more extreme gameplay and weirder storylines. And there can be few players out there who would argue against the case that No Limit City are leading the way. From German U-Boats in Das Boot, to hellish prison wards in San Quentin xWays and evil-looking green devils in Evil Goblins xBomb, NLC seem to enjoy finding new ways to make us uncomfortable. And the peak of that ambition is surely manifested in this dark and sick game that is simple called … Mental!

Those who have found that slot games with a horror theme just aren’t really that unsettling might want to revise that theory after playing this one. It is surely No Limit City’s most sinister title yet and maybe even a little questionable in taste. We thought things had reached the extreme in San Quentin but this takes the shock factor to a whole new level. The game is filled with mental patients – some of whom land dead on the reels – and bodily organs. And during your spins you may experience straitjackets, ice pick lobotomies and electro-shock treatments!

The horror film feel is established right from the start with a sepia design that creates a historical vibe – we’re heading back in time into the Victorian era to look at an insane asylum where barbaric treatments and a grisly atmosphere are the norm. The action takes place on 5 reels with varying rows starting in a 3,2,3,2,3 formation. This can extend to up to 20 rows when certain events trigger, while the paylines offer 108 ways to win.

Mental Game Information

  • Release Date: 2022
  • RTP: 96.08%, 94.20%
  • Variance: High
  • Maximum Win: 66,666x
  • Progressive Jackpot: No
  • Reels: 5
  • Rows: Up to 20
  • Paylines: 108+
  • Minimum Stake: £0.20
  • Theme: Horror
  • Features: Fire Frames, Dead Patients, Enhancer Cells, Free Spins, Multipliers

What We Liked

  • Daring insane asylum theme
  • Up to 9,999x Multipliers
  • 3 Free Spins rounds
  • Gruesome graphics and eerie soundtrack
  • Lots of splitting cells and xNudge Wilds

What We Didn't like

  • May be too disturbing!
  • Variance too high for some players

Mental Review Scores

  • Theme and Design 9
  • RTP and Variance 8
  • Maximum Win 10
  • Symbols and Paytable 9
  • Features and Gameplay 9

What Our Reviewer Says ...

"A seriously creepy horror slot from the dark masters with full-on high variance features!"

Overall Score: 9.0

RTP and Variance

Our Score 8

What is RTP?

RTP (Return to Player) refers to the amount a game will pay out in cash prizes expressed as a percentage of all the money wagered on that game. For example, a 96% RTP means a game will pay out £96 for every £100 wagered. This is an average number and will vary from one session to the next.  Read more here.

What is Variance?

Variance refers to how far a game will deviate from its RTP over time. High variance games deviate a lot and produce uneven win distributions and unexpected windfalls. Low variance games provide a more stable and even distribution of wins. Read more here.

The RTP of this slot is 96.08%, which is about average for online slots. The minimum bet is 20p and as expected from No Limit City slots, the volatility level is extreme. It’s published as 10/10 by NLC and it feels as rough as anything by their team before now. To be fair everything about this game is extreme and it’s definitely a risky play, so you need to be prepared for big swings in payouts.

With such an uneven win distribution, a large bankroll will help ride out the lean spells, while playing at lower betting levels could help to stretch out your gaming session too. The top payout is advertised as 66,666x (of course!) and is an event that actually has a name – This Is Mental!!! The odds of unlocking it are 1 in 18 million so don’t hold your breath. What we do know is that there is a myriad combination of features to work through and unlocking particular combinations of multipliers, wilds and expanding reels is the only way to get even close to that max win.

The game has a hit frequency of 34.19% – that tells you how many times on average a spin will trigger a win. The free spins round which opens the gates for bigger wins triggers one in 216 times on average.

Symbols and Paytable

Our Score 9

In Mental Slot you’ll receive a payout if you manage to find 3 or more matching symbols on a payline from left to right. There are 108 win ways initially, but thanks to splitting symbols and extending reels, that figure can rise.

The symbols are all themed around asylum life with 5 mental patients on the reels, along with body parts. You’ll find skeleton hands, eyes, kidneys, brains and hearts to award the lower payouts.

The premium symbols are the patients of the asylum, all given a number from 1 to 5 and pictured in various states of ‘treatment’. These patients can pay from 1.5x to 5x stake for 5 of a kind with patient number 1 (the one wearing a mask, Hannibal Lector style) awarding the highest payout.

Features and Gameplay

Our Score 9

This is a complex game with a lot going on so it will take quite a few spins to figure it out. Here we break those features down one by one to help you understand what each one does.

Fire Frames

In the base game up to 13 tiles could take a Fire Frame, surrounded by flame animations, and any symbol landing here will split to create 2 new symbols.

Dead Patient

Landing 2 dead patient symbols will activate a random Multiplier, which could be an of these values:  5, x10, x15, x30, x50, x100, x300, x500, x1,000, or x9,999. That’s an extreme multiplier feature and numbers those high are a rarity in slots.

Enhancer Cells

On the bottom row of the second and fourth reels are two Enhancer Cells, which can be activated by landing 4 and 6 Fire Frames on each. When the Enhancer Cells are active any of the following events triggers:

  • Any of the five patient symbols
  • A dead patient symbol
  • xWays that can reveal new symbols and expand the reel height
  • xSplit that can split the other symbols and turn into a Wild
  • Wild symbols that substitute for other symbols on the reels
  • xNudge Wild stacks that nudge up or down to fully occupy the reel. Each nundge as 1x to a progressive Multiplier

Mental Transform

Landing the creepy spider symbol on reels 2 and 4 triggers the Mental Transform feature. The spider can transform into a dead patient, regular patient, Wild, xWays or xSplit symbol.

Free Spins Modes

If your brain isn’t hurting like electro-shock therapy yet, it will be soon! Let’s move onto those THREE free spins rounds, each with it’s own manic combination of features.

Autopsy Free Spins

Scorpion symbols appear on reels 1, 3 and 5. Hitting 3 scorpions triggers 8 Autopsy Free Spins, while spiders with Fire Frames will award 1 extra Free Spin. Fire Frames will appear on up to 5 symbols and stick into position for the duration of the round.

If at any point a Spider lands on the reels in this round then you can upgrade your spins to one of the following.

Lobotomy Free Spins

Landing 3 scorpions and 1 spider symbol will trigger 9 Lobotomy Free Spins. The rules from the Autopsy free spins carry over and more are added. Now, the spider symbol becomes sticky and the Mental Transform feature triggers on every spin. You’ll also receive Dead Multipliers from all the dead patient symbols collectively to award up to 15x Multipliers.

During this round, if you land two Spider symbols you will upgrade to Mental Free Spins too.

Mental Free Spins

Landing 3 scorpions and 2 spiders will trigger 10 Mental Free Spins. In this round, you’ll receive all the features of Lobotomy Free Spins, plus both spiders become sticky for the duration of the round to trigger Mental Transforms on every spin.


There is a way to buy into the free spins but this feature is only available to players outside the UK. You can pay up to 1,000x to buy 11 Autopsy Free Spins, 13 Lobotomy Free Spins or 15 Mental Free Spins.

The Final Verdict

To our minds, Mental is the most sinister slot available online today, with a truly creepy Victorian insane asylum that grabs your attention and keeps you hooked, it’s packed with macabre imagery, the strongest of which must be the ice-pick-in-the-eye lobotomy. This is dark stuff for sure and maintains No Limit City’s current position as kings of weird.

For those with the stomach to handle the grim atmosphere, there is plenty to go out in terms of features and maths. Some might say too much as at times it can feel like there are too many events happening on screen to be able to follow properly.

For big win chasers who are in for the long run – and you have to be to get anything back from this game – the 3 Free Spins rounds are the holy grail. When combining with Wilds, split symbols and Multipliers, which can go as high as 9,999x in the Dead Patient feature, the payouts can escalate quite quickly and deliver on the promise of potential in the game profile.

And finally, if you do ever hit the top payout of an ominous 66,666x stake, you’ll receive the triumphant message ‘This is Mental’!!!

It certainly is.


Useful Resources

No Limit City Mental Slot Game Profile Page

Who Made Mental?

  • Name: Nolimit City
  • Established: 2016
  • UK License: Remote 052097-R-329532-005
  • Total Games: 50 +
  • Known For: Super high variance, super high maximum wins, adult themes, irreverent humour
  • Popular Slots: San Quentin xWays, Mental, Book of Shadows, Tombstone RIP
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