Nitropolis slot review

Nitropolis slot in brief

Nitropolis arrived from Swedish studio ELK in 2020, a year after Cygnus, and takes ELK’s interest in growing grids in a different direction. Instead of adding rows, it compresses lots of symbols into a small space. The setting is a neon, futuristic city, and the reels look tidy at a glance: 6 columns and 4 rows. The interesting part is the block that sits on each reel.

Nitro Reels explained: how one block holds up to 12 symbols

A Nitro Reel is a block that takes up two symbol places on a reel but represents several copies of the same symbol: at least 4 and as many as 12. For counting ways, those copies all count. A reel with a Nitro Reel holding 8 symbols therefore contributes far more than the 4 positions it appears to show, and because ways are multiplied across all 6 reels, a few large Nitro Reels push the total up very quickly.

ELK’s description gives Nitro Reels three behaviours:

The upgrade is what drives the headline figure. 85,155,840 ways is the theoretical ceiling when every reel’s Nitro block is at a high count; most spins sit far below it. Our guide to ways to win explains the counting method in general terms.

Winning Respins: how wins carry on

Nitropolis does not use a standard tumble. After a win, every symbol that contributed to it respins on its own, while the rest of the grid stays put. If the respun symbols create a new win, those symbols respin too, and the sequence continues until a spin produces nothing.

This is a subtle but useful difference from a cascading reels game. Because non-winning symbols stay where they are, a strong Nitro Reel on one reel can remain in place while the winning positions around it get further chances to line up. It is a close cousin of a respin feature, applied to individual positions rather than whole reels.

All of these respins happen within one paid spin. You are only charged your stake once, and UK timing rules apply to the start of each paid spin.

How to play Nitropolis

1. Open the help screen and check the RTP figure and the symbol values for 3 to 6 of a kind.
2. Pick your stake. In the UK the most you can bet is £5 a spin at 25 and over, or £2 if you are 18 to 24.
3. Spin and watch the Nitro Reels; the ways counter shows how many ways the current blocks create.
4. If the spin wins, the winning symbols respin individually until no new win appears.
5. After a losing spin, a Nitro Reel may respin on its own for a second chance.
6. Land three or more bonus symbols to start free spins with sticky Nitro Reels.

Nitropolis free spins: sticky Nitro Reels and scatter pays

Three or more bonus symbols trigger the free spins round, which awards up to 25 spins. Two things change once it starts.

• A scatter-paying symbol is picked at random. That symbol pays wherever it lands, not just on adjacent reels, adding a second way for it to win on each spin.
• All Nitro Reels lock. They stay sticky for the remaining spins, so any block that has upgraded keeps its symbol count for the rest of the round.

The bonus can be retriggered, and each retrigger adds another scatter-paying symbol. A round with several scatter symbols and large sticky blocks is where the 10,000x cap becomes reachable, though most rounds finish well short of that. Read about scatter symbols for the general mechanics.

What 85 million ways really means for your stake

Huge ways figures look impressive in a lobby, but they do not make a game more generous. The paytable is set so that the overall return still averages 96.1%, whatever the ways count. When ways climb, individual symbol payouts are small in proportion: a combination that hits thousands of times in one spin pays a tiny amount each time, and the total is what matters.

A better question is how the game spreads its 96.1%: here, a lot of it is reserved for free spins with locked Nitro Reels. That is what the medium–high volatility rating describes. Our explainer on whether Megaways slots are better covers the same misconception for another big-ways format.

Nitropolis RTP: 96.1% in pounds

The published RTP is 96.1%, so the average cost of play is 3.9% of everything you stake. Here is what that means for three typical sessions.

The averages hide large swings. On a medium–high volatility game, the 40-spin session at £2 is much less likely to include a bonus than the 150-spin session, so its result will probably sit further from the average in either direction. Check the help screen for the figure at your casino and see our guide on how to find a slot’s RTP.

Nitropolis max win: 10,000x stake

The top prize is 10,000x your stake. That is £2,000 at 20p, £6,000 at 60p, £20,000 at £2 and £50,000 at £5. On most slots, a round that reaches the cap stops there and pays the capped amount; the help screen confirms how this game handles it. Getting there needs a free spins round with multiple scatter-paying symbols and high sticky Nitro counts, which is very rare. Our page on high max win slots compares caps across games.

UK rules: no Buy Bonus, no autoplay

ELK’s game page describes two paid entries, a standard bonus and a super bonus that includes a retrigger. Neither is offered to players in Great Britain, because feature buys are not available here. UK versions also have no autoplay or turbo, take at least 2.5 seconds per spin, and cap stakes at £5 or £2 depending on age. Demos require age verification. The UK slot stake limits guide explains the age bands.

Nitropolis sequels and ELK’s other games

ELK has followed Nitropolis with numbered sequels that build on the Nitro Reel idea, each with its own RTP, cap and features, so check the help screen rather than assuming they match this game. The studio’s other best-known games include the Wild Toro walking-wild series and the bird-collecting Pirots series. Our how slot sequels differ guide explains what usually changes between instalments.

Nitropolis vs other big-ways slots

Nitropolis has by far the biggest ways number in this group, yet both Big Time Gaming games carry higher caps, and White Rabbit has a higher published RTP. That is a good illustration of why ways count alone is a poor guide to a slot’s value. More big-ways games are listed on our Megaways slots page.

Nitropolis pros, cons and who it suits

Nitropolis suits players who enjoy feature-driven games and are curious about new reel mechanics. Those who prefer steady base-game returns and simple paylines may find it too dependent on the bonus.

Where to play Nitropolis

Search for Nitropolis in the lobby of a UKGC-licensed casino and check the RTP in its help screen. 10bet gives new UK customers aged 18+ a 100% match up to £25 when they choose the casino welcome bonus at sign-up and deposit within 7 days; the bonus must be wagered 10x on slots within 3 days and bonus winnings are capped at £1,000. Terms apply. Our 10bet slots guide covers its lobby.

18+. Gambling should be entertainment that costs money, not a way to make it. Set a deposit limit before you play: how to set limits. Free, confidential help: National Gambling Helpline 0808 8020 133.