Nitropolis 4 Slot Review 2024

ELK Studios‘ gang of Dirty Dawgs, Gritty Kitties, Pug Thugs and Rogue Rats are back for a 4th and possibly final time, in Nitropolis 4!

Eat-sleep-drill-repeat! After some much needed respite, the gang is ready and raring to get back in on the action. On their travels they come across a disused oil rig offshore that can easily be drilled into for Nitro. Vacation’s over boys, its time to drill!

ELK Studios and their latest Nitropolis titles have come a long way since the release of the original in 2020, but will the 4th be the final in the series or will ELK find a way to keep them going like the Fast & Furious movies have?

Moving on from palm trees and sand, ELK Studios puts us back into the thick of it in a foggy and desolate oil rig. We don’t usually make a big song and dance about sound effects and music, but it’s always worth mentioning in an ELK Studios slot.

ELK Studios are not only known for their innovative slots, but also for their great taste in sound effects and music. As soon as you hit a big win you know you’re in for a treat, and its no different here, although the big win music is a little more heavy on the eardrums.

With Nitropolis 3 still fresh in our minds, will Nitropolis 4 live up to our high expectations? Let’s play on and find out!

Nitropolis 4 Base Game

Nitropolis 4 Base Game and Features

Nitropolis 4 is a 6 reel slot with 4,096 starting ways to win. Forming a win requires 3 or more of the same symbols to land from left to right, starting from the left-most reel.

The minimum bet available here is £/€0.20 per spin and the maximum bet available is £/€50 per spin, with a small mix of bets in between the two. Nitropolis 4 has a theoretical RTP of 94.00% and a max win cap of 50,000x.

In terms of symbols, the highest paying symbol here is the Dog with the Red background, followed by the Cat, Pug, Rat, Dirty Dawgs, Gritty Kitty, Pug Thugs and Rogue Rats crest symbols. Low-paying symbols are standard Ace, King, Queen and Jack.

Wild symbols are present on all reels, substituting for all other symbols in the paytable except Scatter and Super Scatter symbols.

Sticking to tradition, Nitropolis 4 has a number of exciting yet slightly confusing features for you to indulge in. More on these below!


All winning symbols across the reels will explode, leaving behind spaces for new symbols to take their place.

Once this happens, an additional row of symbols is added at the top, up to a maximum of 8 rows. Nitro Reels and Nitro Multipliers that are part of a winning combination will also Respin. The Avalanche feature will continue until no new winning combinations are formed.

Big Symbols

During the base game, Super symbols of 2×2 and Mega symbols of 3×3 in size can randomly appear during any spin or symbol drop, including Wilds.

Nitro Reels

When present on the reels, Nitro Reels cover 2 symbol positions which can contain 4, 6, 8, 10 or 12 1×1 payout symbols within them.

Big Nitro Reels will naturally cover 6 symbols positions and contain 2, 3, 4, 5 or 6 2×2 payout symbols within them.

Nitro Multiplier

Also in play during the base game is Nitro Multipliers. A Nitro Multiplier will cover 2 symbol positions and Multiplies all winning combinations in view with a random Multiplier value of x4, x6, x8, x10 or x12.

Nitro Booster

Above the reel set sits 2 Nitro Booster screens. The Nitro Booster has the power to add Features to the main reels, of which there are 8.

  • Redrop – All Nitro Reels, Nitro Multipliers, Wilds and Scatters are kept in position, whilst other symbols are removed, making room for new symbols to drop in and all reels Respin.
  • Both Ways – Winning combinations are paid from left to right and right to left, starting from both the left-most and right-most reels.
  • Max Rows – Expands the reel set to the maximum height or 8 rows.
  • Nitro Wild – An existing Nitro Reel is filled with Wild symbols.
  • Garbage Collect – All instances of a randomly selected High or Low-paying symbol in view are removed.
  • Nitro Upgrade – An existing Nitro Reel in play is upgraded and additional symbols are added to it.
  • Nitro Appear – A Nitro Reel of any size is awarded, replacing existing symbols in view during the ongoing spin.
  • Nitro Match – An existing Nitro Reel in play is matched with a random High or Low-paying symbol in view and the Nitro Reel is filled with that particular symbol.

Nitropolis 4 Nitro Wild Feature

Nitropolis 4 Free Spins

Landing 3, 4, 5 or 6 Scatters across the reels triggers the Free Spins round, awarding 8, 12, 16 and 20 Free Spins respectively.

Alternatively, landing a combination of regular Scatters and a Super Scatter will automatically trigger the Super Free Spins round which is played with Max Rows and Both Ways modifiers active.

During Free Spins, Nitro Reels are sticky and remain like this until the end of the Free Spins round. In addition to this, the Safety Level advances by +1 row for every new Free Spin that results in a win. Every new free spin will automatically start at the new Safety Level.

Nitropolis 4 Free Spins

Nitropolis 4 X-iter Feature

Those outside the UK will benefit from ELK Studios X-iter Feature. Here you will be able to choose from 5 exciting Options, as follows.

  • Bonus Hunt – More than Doubles your chance of triggering the Free Spins round for a total cost of 2x your current bet.
  • Nitro Booster1 Spin with 2 guaranteed features every time the Nitro Booster activates for a total cost of 10x your current bet.
  • Super Spin1 Spin with Max Rows and Both Ways active for a total cost of 25x your current bet.
  • Free Spins – Triggers the Free Spins round with Sticky Nitro Reels for a total cost of 100x your current bet.
  • Super Free Spins – Triggers the Super Free Spins round with Sticky Nitro Reels, Max Rows and Both Ways for a total cost of 500x your current bet.

Nitropolis 4: Our Verdict

If we’re honest, we thought we’d seen the end of the crew when Nitropolis 3 dropped, but the gang just won’t stop in their perpetual quest for Nitro. Is the Nitropolis series becoming one of ELK’s staple series.

In Nitropolis 3 ELK Studios addressed a lot of the issues that made Nitropolis 2 just short of great, so in Nitropolis 4 the foundations are laid for some polished improvements to make it even better, but is it? Nitropolis 4 certainly improves on Nitropolis 3 in our opinion, as any sequel should.

Nitropolis 4 feels action-packed, and it really reaffirms our appreciation for the Nitro Reels, which have come a long way since the start of the series. Again, Nitropolis 4 certainly feels like a game more catere

d towards a bonus buy market, but the absence of these features in the UK market isn’t ELK’s fault. However, ante bet features still exist, and we’d love to see at least the bonus hunt feature present in the UK market to further enhance the appeal of Nitropolis 4.

The likelihood of seeing a Super Bonus in Nitropolis 4 if you’re within the UK is slim, but it’s possible and if you do get it, then you’ll see Nitropolis 4 in full swing with potentially gargantuan hits.

When it comes to stats, Nitropolis 4 looks great with up to 50,000x as a maximum win, but the RTP is fairly disappointing at 94%

Overall, Nitropolis 4 isn’t a huge reinvention from Nitropolis 3, but makes improvements where it matters, and it has the potential to kick off at any moment.