Play money · no sign-up · no deposit
- RTP
- 96.07%
- Volatility
- Very high
- Max win
- 15,000x
- Grid
- 6x6
A 6x6 scatter-pays slot where every Avalanche win doubles a multiplier ladder, and free spins can lock the level you reached for the spins that follow.
Written by Hampus GravePublished 11 Nov 2026
7.2/10
Only if you are a bonus buyer with the balance for it. The ladder resets every base round, so the real game is Free Spins, where a Multiplier Lock saves the level reached for later spins. The drawback is the price of getting there: 40 of our 100 base spins paid, but none of them reached a bonus.
Who it suits
Play this if…
- You are a bonus buyer who wants the top round: Super Free Spins puts a Giant Symbol on every spin
- Multipliers that build across a bonus are your favourite part of a slot: a Multiplier Lock carries the level into the next spin
- You chase ceilings and accept dry stretches: Slotmill's label is Very High and the bonus ladder runs on to x32768
Skip this if…
- You are spinning the base game for its wins: the ladder is wiped at every new round
- You are a bonus chaser on a small balance: no trigger rate is published, and Free Spins need three Bonus symbols at once
- RTP comes first for you: the casino chooses between two versions, about two points apart
Casinos we recommend
Dr. Brainfart is not out yet. These are the casinos we recommend, with YEET as our #1 pick. How we test casinos
- Our #1 pick
YEET
FluxPlays score 9.5
10% weekly lossback
10% weekly lossback for FluxPlays players, applied for in our Discord. On top: weekly and monthly bonuses and instant rakeback. Code FLUXPLAYS.
18+ · T&Cs apply · Offer checked 11 Nov 2026
SafeCasino
FluxPlays score 7.5
Skrill withdrawal paid out in 18 hours in our test
400% up to €4,000 + 1,200 free spins
- 40x wagering
- min deposit €10
- 30 days
400% welcome package up to 4,000 over four deposits, each 100% up to 1,000 plus 300 free spins. 40x wagering on bonus and free spin winnings. Minimum 10 to activate, 200 for the full 300 spins. 30 day validity. Free spins run on Pragmatic Play games.
18+ · T&Cs apply · Offer checked 7 Oct 2026
Betlabel
FluxPlays score 7.0
E-wallet payout inside 24 hours in our test
200% up to €1,500 + 150 free spins
- 35x wagering
- min deposit €10
- 7 days
200% welcome package up to 1,500 plus 150 free spins over four deposits: 100% up to 300 + 30 FS, 50% up to 350 + 35 FS, 25% up to 400 + 40 FS, 25% up to 450 + 45 FS. 35x wagering, 7 day window. Minimum 10 first deposit, 15 thereafter. Crypto deposits are not bonus eligible.
18+ · T&Cs apply · Offer checked 7 Oct 2026
These are affiliate links: we earn a commission if you sign up through them. It never changes our scores. Affiliate disclosure
Dr. Brainfart: Full Review
By free spin 5 of 8, the 300x Super Free Spins buy in Dr. Brainfart had already banked its final $357.70, and the last three spins added nothing. Slotmill releases this 6x6 scatter-pays slot in November 2026, and we played the pre-release demo, which you can open free from this page. Every Avalanche win doubles a multiplier ladder, so it suits bonus buyers more than anyone hoping the base game will carry them.
Dr. Brainfart game information
- Provider
- Slotmill
- Release date
- 17 November 2026
- Grid
- 6 x 6 (reels x rows)
- How it pays
- Pay anywhere, 8+ symbols
- RTP
- 96.07% (casinos may also run 94.08%)
- Volatility
- Very high
- Max win
- 15,000x the bet
- Bet range
- $0.20 to $100
- Buys and modes
- 2 buys, 3 paid modes, see the table
How Dr. Brainfart works
One number above the grid runs this game. Eight or more of a symbol anywhere is a win, winners explode, new symbols drop in, and the Avalanche carries on while fresh wins form. Each Avalanche win doubles the win multiplier along a ladder that opens x1, x2, x4, x8, x16, and the ladder goes back to the bottom when a new round starts.
| Symbol | 8 | 10 | 12 | 14 | 16+ |
|---|---|---|---|---|---|
| Dr. Brainfart | $0.75 | $1.20 | $2.25 | $5 | $10 |
| Each gem | $0.30 | $0.50 | $0.75 | $1.50 | $3 |
The four other picture symbols pay between those two rows. We could match only these two rows to a capture, so the table leaves the rest out.
Two extras can speed up a chain. Any paying symbol can arrive as an Xcelerate symbol, and when one is part of a win it strikes one of the four upcoming multipliers off the meter, shortening the climb. Giant Symbols, 2x2 or 3x3, can appear at the start of a round or once wins run out, and count as 4 or 9 of their type.
The opening board, with a 2x2 Giant Symbol and the ladder from x1 to x16. FluxPlays demo test, 10 November 2026.
Free Spins and Super Free Spins: how they trigger
A trigger takes three, four or five Bonus symbols, worth 8, 10 or 12 Free Spins. Make one of them a Super Bonus and the same counts award Super Free Spins instead. Neither round can be retriggered.
The ladder stops being disposable here. At the start of each free spin the meter falls back only to the lowest saved multiplier, and steps struck off by Xcelerate symbols stay gone for the whole bonus. Saving is the job of the Multiplier Lock, which needs a win to activate. Once active it keeps the spin going through every consecutive Avalanche win, then stores the level reached as the starting point for the spins that follow.
Super Free Spins add one thing to all that: a Giant Symbol on every spin. That is what the higher price pays for, and for us it is the reason to prefer the Super round.
Free spin 5 of 10 from the 100x buy, with the lit slot of the ladder on x64. FluxPlays demo test, 10 November 2026.
The first of 8 Super Free Spins, with Giant Symbols on the grid. FluxPlays demo test, 10 November 2026.
Fast Track and Xtra-Bet: prices and what you get
Fast Track belongs to the base game and charges its price on every spin while it stays on, so switch it off once you have the round you wanted. Multiplier Boost starts the ladder on a random multiplier, and Super Xtra-Bet lifts the chance of Super Free Spins without guaranteeing them.
Buys and paid modes
Prices at a $1 bet, with our test result
Free Spins Bonus
$100
Bonus buy · RTP 96.43%
Guaranteed Free Spins
Our testOne round: $50 back ($100 in)
Super Free Spins Bonus
$300
Bonus buy · RTP 96.47%
Guaranteed Super Free Spins, a Giant Symbol on every spin
Our testOne round: $357.70 back ($300 in)
Multiplier Boost
$40 a spin
Paid mode, per spin · RTP 96.20%
Random starting multiplier on each spin
Our test10 spins: $224.80 back ($400 in)
Super Xtra-Bet
$7 a spin
Paid mode, per spin · RTP 96.21%
Higher chance of Super Free Spins
Our test10 spins: $31.45 back ($70 in)
Xtra-Bet
$1.50 a spin
Paid mode, per spin · RTP 96.18%
2.8 times the Free Spins chance, wins evaluated on the base bet
Our test10 spins: $5.55 back ($15 in)
| Option | Price at $1 | Official RTP | What you get | Our test |
|---|---|---|---|---|
| Free Spins BonusBonus buy | $100 | 96.43% | Guaranteed Free Spins | One round: $50 back$100 in |
| Super Free Spins BonusBonus buy | $300 | 96.47% | Guaranteed Super Free Spins, a Giant Symbol on every spin | One round: $357.70 back$300 in |
| Multiplier BoostPaid mode, per spin | $40 a spin | 96.20% | Random starting multiplier on each spin | 10 spins: $224.80 back$400 in |
| Super Xtra-BetPaid mode, per spin | $7 a spin | 96.21% | Higher chance of Super Free Spins | 10 spins: $31.45 back$70 in |
| Xtra-BetPaid mode, per spin | $1.50 a spin | 96.18% | 2.8 times the Free Spins chance, wins evaluated on the base bet | 10 spins: $5.55 back$15 in |
Xtra-Bet is a separate switch and cannot run together with Fast Track. It adds half again to the bet and makes the Free Spins Bonus 2.8 times as likely, with wins still evaluated on the base bet.
The Fast Track menu at a 1.00 bet. FluxPlays demo test, 10 November 2026.
RTP, volatility and max win
The base game runs at 96.07%, and Slotmill also lists a 94.08% version, so the casino's pick matters. Slotmill's own label is Very High. A round that reaches the cap ends there and pays 15,000x the bet.
Our Dr. Brainfart demo test
FluxPlays demo test
10 November 2026, demo running 96.07% base, 96.43% Free Spins Bonus, 96.47% Super Free Spins Bonus, 96.20% Multiplier Boost, 96.21% Super Xtra-Bet, 96.18% Xtra-Bet (the game's rules) RTP
Base game spins
100
at $1 per spin
Staked
$100
Paid back
$48.30
48.3% of stake, -$51.70
Winning spins
40 of 100
40% of spins paid something
Biggest win
$7.60 (7.6x)
a long Avalanche run in the base game; no bonus in the 100 base spins
Free spins triggered
0
natural triggers in the session
Played on Slotmill's pre-release free-play demo at dr-brainfart.slotmill.com on 10 November 2026, ahead of the 17 November 2026 release, in USD demo credits from a 10,000.00 balance at a 1.00 bet. Build number not shown. The 100 base spins ran first; one more autoplay round was played and lost and is not counted. Each buy was then played once and each paid mode for 10 spins. Every round was reconciled to the on-screen balance, 9,731.80 at the end. Per-step amounts inside the free spins were not logged. Re-check on release day.
Between the buys the base game produced a lot of very small numbers. It paid on 40 spins but reached twice the bet on only 7 of them, and a long Avalanche run on spin 66 gave the best of the lot, $7.60. No spin outside the two bought rounds reached a bonus.
The final amount of the 100x Free Spins Bonus. FluxPlays demo test, 10 November 2026.
The final amount of the 300x Super Free Spins Bonus. FluxPlays demo test, 10 November 2026.
Multiplier Boost showed what a higher start does and does not do. Eight of its ten spins opened at x4 or above, yet six of the ten paid nothing, since a head start only counts once a win lands. One spin that opened at x8 returned $120.80.
Ten spins of a mode and one round of each bonus show how they behave, and say nothing about what they return over time.
The Super round decides whether Dr. Brainfart is for you
Its bonus menu earns a look and its base game does not. Nothing built in a base round survives into the next one, which is the opposite of what a Multiplier Lock does inside free spins, so the appeal sits almost entirely behind a trigger or a price.
Emberfall is the obvious comparison, from the same studio with the same 6x6 grid and the same doubling on every Avalanche win. Pick Emberfall if you want free spins that keep every step to the end. Pick Dr. Brainfart if saved levels and a Giant Symbol on every Super spin interest you more.
In the demo, run a few Multiplier Boost spins first. They are the cheapest way to see the ladder open above x1.
Frequently Asked Questions
How do you trigger the free spins in Dr. Brainfart?+
Land three, four or five Bonus symbols anywhere for 8, 10 or 12 Free Spins. If one of them is a Super Bonus, the same counts award Super Free Spins instead. Neither round can be retriggered, and both reached us only by buying them.
Can you buy the bonus in Dr. Brainfart, and what does it cost?+
Yes, through Fast Track in the base game. The Free Spins Bonus costs 100x the bet and the Super Free Spins Bonus 300x, and each guarantees its round. The charge repeats on every spin while Fast Track stays on, so switch it off after the round.
What does the multiplier do in Dr. Brainfart?+
It doubles with every Avalanche win, climbing from x1. In the base game it returns to the bottom at the start of each round. In free spins it falls back only to the lowest saved level, and a Multiplier Lock is what saves a higher one for the spins that follow.
What is the max win in Dr. Brainfart, and how is it reached?+
The max win is 15,000x the bet. A round whose total reaches that figure ends at once and pays it. The doubling ladder in the bonuses is the route to it, and Slotmill publishes no odds of getting that far.
More slots like Dr. Brainfart
Emberfall 40k
Slotmill
7.6 / 10
Duck Hunters 2
Nolimit City
8.8 / 10
Comments
Played it, tried it or have a question? Share it with the community under this slot page.