Nitropolis 4

Nitropolis 4 (ELK Studios) Slot Review


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Nitropolis 4: Slot Overview

You know the phrase „Third time’s the charm“? It pretty much refers to something like „If the first too attempts didn’t go as planned, it will probably work on the third try.“ But ELK Studios thought „Nah, we’ll just make it a four“ and now there it is. In this online slot review we will be going over the fourth iteration of the street gangs of Nitropolis 4.

Nitropolis 4 is played on 6 reels with 4 to 8 rows and makes use of Winning Ways. In combination with all the different features, that we’re gonna go over in our Feature Overview section, there are massive amounts of Win Ways possible. In fact it’s so many that ELK Studios themselves didn’t even cap it, or at least didn’t mention any cap. Bet sizes range from 0.20€ to 100€ (or equivalent), and may vary depending on where you play.

So, let’s start with the winning symbols. There are 12 symbols that will help you getting wins, with 4 of them on the lower, 4 on the mid and 4 on the higher end. Let’s begin with the low tier symbols, these are pretty classic in old Nitropolis style, from J to A. And they all actually share the same payout. You will get 0.3-times your bet for any full way of these symbols.

Next up we have the mid tier symbols. These consist of the street gangs’ signs again, but this time they have a harbor-theme, since the whole game is placed on some sort of oil rig or harbor. So we have the Rogue Rats and the Pug Thugs, coming in at 0.8-times your bet size for a full way, followed by the Gritty Kitty and the Dirty Dawgs for 1-time your bet size.

On the higher end are the gang leaders, just like in past iterations. First we have the Blue Rat for 1.25-times your bet size, then the Green Pug, clocking in at 1.5-times your bet size, the Purple Kitty for 2-times your bet sizes, and as always, the one and only Red Dog for 3-times your bet size for a full way.

Nitropolis 4: Special Symbols and Stats

As usual, Nitropolis 4 has a lot of special symbols to offer.

Let’s start with the Nitro Reels. These can come randomly in any spin and are portrayed by a green frame with a number on them. They are two positions high and the number shows how many symbols they currently hold. They can hold 4, 6, 8, 10 or 12. The symbols inside the Nitro Reel are the same. So for example, if a Nitro Reel holds the Red Dog, all of its symbols are Red Dogs. There are also Big Nitro Reels, which cover six symbol positions and contain 2, 3, 4, 5 or 6 2-by-2 symbols. Once Nitro Reels were part of a winning combination, they are „re-rolled“ so that you have a chance on a new symbol.

The Nitro Multiplier is another two position high Special symbol that can come in randomly in any spin. It is portrayed by a green gas tank and can hold multipliers between x4 and x12. While these are on the screen, they multiply any wins in view. These are also re-rolled once they applied their multiplier to a win.

We also have Big Symbols again, just like in the predecessor. These can drop in any spin and can be in the size of 2-by-2 or 3-by-3. By the way, if you land a Big Symbol and it doesn’t actually fit on the screen, you will get extra rows without doing anything.

Of course we also have a Wild symbol again. This time the Wild symbol is portrayed as a sea mine and the label „WILD“. It substitutes for any winning symbol except Scatters.

Talking of Scatters, of course Nitropolis 4 has these. This time they are portayed like a cyclopse submarine and the label „BONUS“. Land 3 or more of these in the same spin to trigger Free Spins. There are also Super Bonus Scatters, these are 2 positions high and look the same like the normal Scatters, but have the label „SUPER BONUS“.

Now for some stats. There aren’t many we can give you unfortunately. The base RTP of Nitropolis 4 is 94.00%, which is far below average and kinda dampens our desire to really play it that much. The max win potential however is capped at 50,000-times your bet size, which is massive, but we have doubt that this will ever happen. Seeing max wins at ELK Studios games is something that rarely ever happens.

Nitropolis 4: Feature Overview

Nitropolis 4 comes with some interesting features that we will take a look at and describe to you as best as we can.


Avalanche is ELK Studios’ way of saying that they use tumbling wins, which means that a spin only ends when nothing else is possible. On a tumbling win, you will unlock an additional row up to the maximum of 8 rows. Rows are reset in base game after every spin.

Nitro Boosters

Nitro Boosters are the 2 screens that you see above the playing grid. These only activate in base game if you unlock another row. That doesn’t mean though that you will get a Nitro Booster everytime you unlock a row. There are 8 Nitro Boosters in total which we will cover in short:

  • Redrop – New symbols drop in and all reels respin, Nitro Reels, Multipliers, Wilds and Scatter symbols are kept.
  • Both Ways – Winnings are paid out from left to right and from right to left.
  • Max Rows – Unlock all 8 rows.
  • Garbage Collect – All instances of a randomly selected symbol in view are removed.
  • Nitro Appear – A Nitro Reel of any size is placed on the grid.
  • Nitro Wild – One Nitro Reel in view is randomly filled with Wild symbols.
  • Nitro Upgrade – One Nitro Reel in view is upgraded and filled with symbols.
  • Nitro Match – One Nitro Reel in view is matched with another symbol in view and then filled with this symbol.

Free Spins Feature

Land 3 or more Scatter symbols on the same spin and you will be granted 8 Free Spins. Additional Scatters grant +4 Free Spins per Scatter, up to a total of 20 spins and therefore 6 Scatters. During Free Spins, all Nitro Reels landed are sticky, which means that they are not reset on the next spin. Additionally, the Free Spins feature uses Safety Levels, a technique common with many of the „Gold“-games of ELK Studios. Upon onlocking your first row, the Safety Level comes in play. Your next Free Spin will always start from your current Safety Level, which will always advance by a maximum of 1 row whenever you have a win during a Free Spin. During Free Spins you have the chance to get Nitro Boosters on the start of every spin, as well as everytime you unlock a row and on every winning combination once you unlocked all rows. Free Spins can be retriggered if 3 or more Scatters are landed in the same spin. They award as many spins as they do when triggered in the base game. Retriggering with a Super Scatter will upgrade the remaining spins to Super Free Spins.

Super Free Spins

To get into Super Free Spins, you will need to land a Super Scatter symbol together with at least 2 other normal or Super Scatters. Land 3 or more Scatter symbols on the same spin and you will be granted 8 Free Spins. Additional Scatters grant +4 Free Spins per Scatter, up to a total of 20 spins and therefore 6 Scatters. During the Super Bonus you will play with Max Rows and Both Ways from the start and for the whole duration of the feature.. Other than that the Super Free Spins basically work like normal Free Spins.


X-iters are the Bonus Buy Features of ELK Studios. Usually their games come with 5 different options to choose from. Here’s a short overview of the available options and what they do:

  • Bonus Hunt for 2-times your bet size – More than double the chance to trigger the bonus game.
  • Nitro Booster for 10-times your bet size – One spin with 2 guaranteed features every time the Nitro Booster activates.
  • Super Spin for 25-times your bet size – One spin with Max Rows and Both Ways activated.
  • Bonus Buy for 100-times your bet size – Guaranteed entry to the bonus game.
  • Super Bonus Buy for 500-times your bet size – Guaranteed entry to the Super Bonus game.

Unfortunately we do not have any information if these buys have a different RTP than the base RTP of 94.00%, but we don’t think so.

Nitropolis 4: Conclusion

For the fourth time now ELK Studios made it their job to tell the story of the gangs of Nitropolis. And for the fourth time now they actually managed to design a very decent game. The details, the music, the design of the winning symbols, it all fits the theme perfectly and has a great vibe to it. One thing is for sure, ELK Studios really cares about the design of one of their finest game series.

But unfortunately the lower-than-average RTP of 94.00% is a downer. Many people might think that a 2% difference, as oppose to the average 96.xx% is not that big of a deal, and for most players it probably won’t be. But for people who really want to enjoy the game on long terms, they will definitely notice a difference, especially since Nitropolis 4 also has a high volatility.

But if you don’t care about that than you will most definitely have your fun with Nitropolis 4. It has tons of features to offer, so that it probably won’t get boring that soon. The only thing we would have wished, besides a higher RTP, is a more different approach compared to Nitropolis 3, because the games are very similar in the way they work.

This concludes our slot review about Nitropolis 4. It was fun seeing and trying out all of its features. Hopefully we left no question unanswered and we hope you will have lots of fun with it.