- A 5×5 cascading cluster slot from Bullshark Games, set in a ruined wasteland
- Collect winning symbols to unlock four Grid Boosters: Clone, Switch, Wilds and Power Line
- Two bonus games that can run without a set limit, volatility rated 5 out of 5 and a 12,000x max win
Doctor Dust is a Bullshark Games slot released on 9 October 2026. A mysterious plague doctor searches the ruins of a wasteland, collecting parts that unlock tools to change the grid.
The main bonus has no set number of free spins. It keeps going for as long as you keep collecting enough winning symbols, which makes it quite different from most cluster games.
Grid and Cascades
The game uses a 5×5 grid, and wins are made by clusters of 4 or more matching symbols. Every win sets off a cascade, with the winning symbols cleared and new ones dropping in to fill the gaps.
Wild symbols cannot land on their own during a spin. They only appear when the Wilds Grid Booster adds them. Once on the grid, they stand in for every symbol in the paytable.
The Collection Bar
Every winning symbol in a spin is counted, and there is a collection bar next to the grid to track them. The bar has 5 segments, and each one needs 8 symbols to fill.
- Fill 1 segment to get the first Grid Booster
- Fill 2 segments to get the second
- Fill 3 segments to get the third
- Fill 4 segments to get the fourth
- Fill all 5 segments (40 symbols) to trigger the bonus game
The boosters come in a random order, and each one can only be awarded once per spin. In the base game, the bar resets at the start of every new spin, so everything has to happen within a single chain of cascades.
Collecting does not stop at 40 symbols. Every further 8 symbols adds 1 to a number in the middle of the bar, up to a maximum of 4. This number shows how many segments will already be filled when the bonus game starts.
The Four Grid Boosters
Once the grid settles, the unlocked boosters go off one at a time. After each one, the grid cascades and settles again before the next booster triggers.
Clone copies one random row onto 1 or 2 rows next to it. Wilds in the rows being overwritten stay where they are. Any cell multipliers on the copied row are copied too, and if the new row already has multipliers, the values are added together.
Switch picks 1 to 3 random rows and changes every symbol in each row to match the first symbol in that row. Wilds stay as Wilds, and cell multipliers stay in their cells.
RECOMMENDED CASINOS TO PLAY Doctor Dust
Wilds adds 2 to 5 Wild symbols to random spots on the grid. Some are plain Wilds, while others carry multipliers from 2x up to 100x. A Wild’s multiplier becomes a cell multiplier where it lands, and it is added to any multiplier already there.
Power Line clears one random row and one random column, then fills those cells with new random symbols, but no Wilds. Any Wilds already in that row or column stay put. Every cell in the row and column also gets a random multiplier, again from 2x up to 100x. The cell where the row and column cross gets two values, which are added together.
Cell Multipliers
Cell multipliers only come from Power Line and from Wilds with multipliers. When a cell with a multiplier is part of a win, its value is applied to that win. If several cells with multipliers are in the same win, their values are added together first.
There is an important rule to keep in mind. Multipliers are removed as soon as they are used, at the same time as the winning symbols. So a big multiplier pays once, rather than staying on the grid for later cascades.
Surface Search
Collecting at least 40 winning symbols in a base game spin triggers Surface Search. It always starts with a spin that has all 4 Grid Boosters, which go off one by one in a random order after the grid settles.
After that, the collection bar has 4 segments of 8 symbols. Each segment you fill during a spin gives you one Grid Booster on the next spin. As long as you fill at least one segment, you get another free spin. When a spin fills no segments at all, the feature ends. There is no limit to the number of extra spins, and from the second spin onwards the count starts from zero every time.
Any extra symbols collected in the base game after the first 40 also help here, since they pre-fill segments for the start of the bonus.
Toxic Vault
Collecting at least 72 winning symbols in one base game spin triggers Toxic Vault instead. It awards 2 free spins and works like Surface Search, with one key difference: the number in the middle of the bar is already at 4. This means the second free spin is also guaranteed to come with all 4 Grid Boosters.
RTP, Stakes and Volatility
The main RTP is 96.30%, and Bullshark also lists a 94.26% version, so check the game info at your casino. The volatility is rated 5 out of 5, the top of Bullshark’s scale. Default bets run from €0.10 to €75, and the max win is 12,000x the bet, which Bullshark says can be reached in all game modes.
About Bullshark Games
Bullshark Games explains its features in a lot of detail on its own game pages, and Doctor Dust is a good example, with every booster set out step by step. If you want to see how the studio handles a cold setting, our Valhalla: Wild Winter review covers one of its winter games.
Overall
Doctor Dust is one of the more unusual cluster slots around. The collection bar turns every spin into a race to fill segments, and the four Grid Boosters each change the grid in a different way, from copying whole rows to adding Wilds with multipliers up to 100x.
The bonus games are the highlight. Surface Search has no fixed number of spins and keeps going for as long as you fill at least one segment, while Toxic Vault gives you a stronger start with two spins full of boosters.
With volatility rated 5 out of 5, this is a high risk game, and multipliers that vanish after one use mean the big wins need a lot to go right at once. For players who enjoy learning a detailed feature set and watching it come together, it is well worth a look.