Slot types and themes
Every kind of slot explained, by mechanic and by theme, with the best-known examples and what each type means for your session.
By the Best Slots UK team. Last checked .
Slot types and themes: how UK slots are grouped
Slot types describe how a game works; slot themes describe how it looks. This hub gathers both. Type pages cover mechanics such as Megaways, cluster pays, hold and win, cascading reels and progressive jackpots. Theme pages group games by subject, from Egyptian tombs and Norse gods to fishing trips and Christmas.
The difference matters. A mechanic changes the maths: how wins form, how often features land and how far a balance can swing. A theme changes only the artwork, sound and story. Two fishing slots can play completely differently, while an Egyptian game and a space game built on the same engine can feel almost identical once the reels start turning.
Many games belong to both lists. Big Bass Bonanza is a fishing slot by theme and a cash collect game by mechanic; Book of Dead is an Egyptian adventure built around expanding symbols in free spins. The cards below let you approach the same library from either direction, depending on whether you are hunting for a feel or a look.
The main slot mechanics compared
These are the mechanics you will meet most often in UK lobbies, with a reviewed example of each.
| Mechanic | How wins form | Example review |
|---|---|---|
| Paylines | Matching symbols on fixed lines, left to right | Book of Dead (10 paylines) |
| Megaways | Reel heights change every spin, up to 117,649 ways | Bonanza Megaways |
| Cluster pays | Groups of touching symbols anywhere on a grid | Reactoonz (7 × 7 grid) |
| Pay anywhere | 8 or more matching symbols anywhere on screen | Sweet Bonanza |
| Hold and win | Cash symbols lock in place during respins | Big Bass Hold & Spinner |
| Cascading reels | Winning symbols vanish and new ones drop in | Gonzo's Quest |
| Progressive jackpot | Part of each stake feeds a growing prize | Mega Moolah |
Each type page explains the mechanic in detail, compares several games that use it, and links to the full reviews. Megaways slots, cluster pays slots and hold and win slots are good places to start.
Slot mechanics
Slot themes
How a mechanic changes RTP and volatility
Mechanics shape where a game keeps its return. A progressive jackpot is the clearest case. Mega Moolah has an RTP of 88.12%, well below the 96% common elsewhere, because part of every stake goes into the jackpot pool rather than everyday wins. Over £100 of stakes, that is a theoretical cost of about £12 instead of £4, in exchange for a tiny chance at a very large prize. The progressive jackpot slots page explains how those pools work.
Megaways, cascading reels and multiplier features tend to push volatility up, because they can chain several wins together in one spin while many other spins pay little. Classic three-reel and fruit games usually sit lower, with smaller top prizes and steadier returns. High volatility slots and low volatility slots pull together games at each end of the scale.
Themes have no effect on any of this. A Christmas skin on a familiar engine does not change the odds, and seasonal versions of popular games often keep the original maths. The same goes for branded games based on films, bands or TV shows: the licence fee shows up in the presentation, not in better odds.
UK rules that affect certain slot types
Some mechanics work differently in Great Britain. Feature buy is not offered to British players, so games known for a buy button abroad trigger their bonuses only through normal play here; bonus buy slots explains what that means in practice. Every slot, whatever its type, must take at least 2.5 seconds per spin, has no autoplay or turbo, and must not celebrate a return smaller than the stake, which is especially relevant to cascading and cluster games where many small wins land in one spin.
Stake limits apply across every type: £5 a spin for players aged 25 and over, £2 for those aged 18 to 24. UK advertising rules also say gambling content must not appeal particularly to under-18s, so playful themes such as candy or cartoon animals are described here as adult entertainment.
How to use the slot type and theme pages
- If you like how a game plays, open its mechanic page to find others built the same way.
- If you like how a game looks, open its theme page, then check each game's volatility before assuming it will feel similar.
- Compare the RTP and max win in the table on each page.
- Open the full review for features, worked examples and the developer's published figures.
- Check the RTP version in the game's help screen at your casino before staking.
Frequently asked questions
What is the difference between a slot type and a slot theme?
A slot type is about mechanics: how symbols pay, how features trigger and how the game's maths is built. A theme is about presentation: the artwork, music and story. Megaways and cluster pays are types; Egyptian, Norse and fishing are themes. The distinction matters because the type tells you much more about how a session will feel. Two games with the same theme can have very different volatility, while games with different themes can share an engine. The guide to slot themes explained covers how studios use themes.
Which slot type pays out the most?
No type pays out more as a rule. Each game has its own RTP set by its developer, and most mechanics include games with returns around 96% as well as lower versions. The exception worth knowing is progressive jackpots, which often have a lower base RTP because part of each stake funds the jackpot; Mega Moolah's is 88.12%. Whatever the mechanic, the house edge applies in the long run. If return is your priority, compare RTP figures directly on the high RTP slots page and check the version in the help screen.
Are Megaways slots better than normal slots?
They are not better, just different. Megaways games change the number of symbols on each reel every spin, so the ways to win vary, up to 117,649 on Bonanza Megaways. That creates more variety from spin to spin and often higher volatility, with long quiet patches between bigger results. A classic payline slot is simpler and usually steadier. Neither type changes the house edge, which is set by the game's RTP. The answer on whether Megaways slots are better compares the two with worked examples.
Why do jackpot slots have a lower RTP?
Because part of every stake is set aside to build the jackpot. On a progressive slot, a slice of each spin feeds a prize pool that can grow very large, and that slice is not available for everyday wins. The published RTP usually includes the jackpot contribution, but because the jackpot is won so rarely, most players experience a lower return than the headline figure in ordinary sessions. Mega Moolah's RTP is 88.12%, compared with about 96% for many non-jackpot slots. The guide to how progressive jackpots work explains the funding.
Does the theme of a slot affect my chances?
No. The theme is decoration: artwork, symbols, sound and story. Your chances depend on the game's RTP, volatility, hit rate and features, all set in its maths model. A seasonal Christmas or Halloween version of a familiar slot may keep exactly the same maths as the original, or it may change it, so check the review or the help screen rather than assuming. Choosing a theme you enjoy is perfectly reasonable, as long as you also look at the numbers. Seasonal theme pages note where a version's figures differ from the original.
Can I buy features on Megaways or hold and win slots in the UK?
No. Feature buy is not offered to players in Great Britain on any slot type, including Megaways, hold and win and cluster pays games. Abroad, some of these titles let players pay a multiple of their stake to start the bonus round directly, but the British versions remove that option. In the British versions, bonus rounds start when the right symbols land during ordinary spins. Reviews describe the natural trigger and how often it tends to land. The glossary entry on bonus buy explains why the option was withdrawn for British players.
What are 1000 edition slots?
They are updated versions of popular games, usually with a higher max win than the original. Pragmatic Play has released several. Gates of Olympus 1000 raises the cap from 5,000x to 15,000x, and Sweet Bonanza 1000 lifts it from 21,100x to 25,000x, while both keep the familiar look and core mechanic. A higher ceiling usually means more of the return sits in rare results. Comparing the original and the 1000 version side by side is the best way to see the trade-off. The 1000 edition slots page lists the reviewed versions.