Nitropolis 4 Slot Review, Demo Play, Payout, Free Spins & Bonuses

Nitropolis 4 Review

It’s been fun following the animal run dystopian world ELK has conjured up in their action-packed Nitropolis series, and we don’t mind a 4th installment at all. The quirky animals are running a massive oil rig this time, and you start out high up above sea level. The grid expands per Avalanche win, like it also did in Nitropolis 3, and you get both Nitro Reels and Nitro Multipliers. Big symbols can also land, as well as Big Nitro Reels.

There are plenty of things going on at all times, and it’s hard to even blink if you don’t want to miss out. A deep computer-like voiceover lets you know what’s happening at all times though, and it announces each of the 8 Nitro Modifiers as well. The bonus round takes you deep below the sea level, which is a nice contrast to the base game, and there is even a super tier that comes with more benefits. The 50,000x max win hasn’t changed since installment number 3, but the RTP has unfortunately been lowered to 94 %.

Nitropolis 4 Slot - Reels Screen

Nitropolis 4 Slot Features

You need between 3 and 6 matching symbols on adjacent reels from leftmost to the right to win, and the premium character symbols pay between 1.25 to 3 x your stake.

The spiky mine is the Wild symbol, and it can appear anywhere to step in for pay symbols and thus help create or improve wins. Wilds pay the same as the top-tier Doberman roughneck symbol should you land a pure wild win.

Winning symbols are removed via the Avalanche mechanic, and the gaps are filled by new and/or existing symbols dropping down from above. In addition, an extra row is added to the grid, and it can grow up to 8 rows in height. Both Nitro Reels and Nitro Multipliers respin per Avalanche win, and the process goes on as long as you keep winning.

The Nitro Reels symbol occupies 2 positions in height, and it can appear anywhere. Each instance of this symbol contains 4, 6, 8, 10, or 12 regular matching symbols, and there is also a Big Nitro Reel that occupies 6 positions.

This one packs between 2 and 6 2x2-sized symbols of the same kind, and they are always randomly chosen for both Nitro Reel types.

The Nitro Multiplier also occupies 2 positions, but it counts as only 1 symbol. It boosts all wins in view when it appears, and it comes with a multiplier value of x4, x6, x10, or x12. If you land more than one Nitro Multiplier, the respective values are multiplied together before being applied to any win. The multiplier value(s) changes per Avalanche win, just to be clear.

You can land Super Symbols of size 2x2, or Mega symbols of size 3x3, and these are regular symbols of a larger size. They can appear on any given spin, and also wild symbols can land as a big symbol.

There are 2 Nitro Booster displays above the grid, and these will sometimes display different Nitro Booster modifiers. There are 8 possible modifiers that can help you out, and here is an overview of how they work:

• Redrop – at the end of the Avalanche sequence, Bonus symbols and Nitro Reels remain frozen in place while the remaining symbols are replaced.
• Both Ways – you now win both from left to right and right to left.
• Garbage Collect – random symbols are selected to be removed, triggering the Avalanche mechanic.
• Max Rows – the grid is expanded to its maximum height of 8 rows.
• Nitro Appear – at random, a Nitro Reel of varying size will be placed on the grid.
• Nitro Wild – an already existing Nitro Reel will be filled with wilds. If no Nitro Reel is present, this feature will be retained until one appears or the game round completes.
• Nitro Upgrade – a Nitro Reel on the grid will have its value boosted. In the event that no Nitro Reel is present, this feature will be retained until one appears or the game round comes to an end.
• Nitro Match – a present Nitro Reel is matched with a present symbol to make a win.

  

  If that’s not possible, it will be matched with an adjacent Nitro Reel. If that’s also not possible, it’s matched with the most valuable adjacent symbol. If there is no Nitro Reel, the feature is retained until one lands or the round ends.

The Bonus Round triggers from 3, 4, 5, or 6 bonus scatters in view in the same Avalanche sequence, and this awards 8, 12, 16, or 20 free spins, respectively. You get the exact same amount if you retrigger the feature by landing scatters in the bonus round. Nitro Reels remain frozen in place for the duration of the bonus round, and each win raises the safety level by one row. The next drop fills the grid up with symbols to the achieved safety level, up to 8 rows at best.

If you triggered the bonus round with a Super Bonus symbol, you get the Super version.

It comes with the Max Rows and Win Both Ways persistently active from the get-go. As usual, there is an X-iter Feature Buy menu option available, at least in some jurisdictions. It’s not available in the UK for sure, however. Here is an overview of what you can get:

• Bonus Hunt - pay 2x your regular stake to more than double your bonus round chances.
• Nitro Booster - pay 10x your stake to get 2 guaranteed Nitro Booster modifiers.
• Super Spin - pay 25x your stake to get a spin with both Max Rows and Both Ways active.
• Bonus - pay 100x your stake to get a guaranteed bonus round trigger.
• Super Bonus - pay 500x your stake to get the Super Bonus Round.

The 200 Spins Nitropolis 4 Slot Experience

You get to see a longer Avalanche sequence where we max out the grid in the base game, before we purchase the Super Bonus Round close to the 1-minute mark. The triggering spin went on for quite a while though, so the feature doesn’t really start until closer to the 2-minute mark. It plays out for the remainder of the 6:35-minute highlights video, and we can promise you plenty of modifier action all the way.

Review Summary

We don’t mind this series going on for a good while more to be honest, but we do mind the deal-breakingly low 94 % RTP. This is tough to swallow for many people, and not least for experienced players, but newbies might not even know or care too (which is perhaps what ELK is calculating with).

To be fair, many slots come with adjustable RTP ranges, so 94 % is not as uncommon as it used to be. Stats aside, Nitropolis 4 is audiovisually as impressive as ever, and we really enjoyed the oil rig setting.

You're taken to the subsea level when the bonus round triggers, which adds a dramatic effect, and you get a game that’s jam packed with all sorts of modifiers as you might be used to from this dystopian series. There is nothing too revolutionary present here compared to previous installments, perhaps, but it hardly feels old or stale at any point. The brand new setting helps in that regard, and there is hardly a boring moment to be found. All the modifier effects are introduced by a cool sounding voice-over, and the 50,000x potential is solid as ever.

Pros

• Avalanche wins adds rows up to 8 in total
• Regular and Big Nitro Reels with larger symbols
• Multiplying Nitro Multipliers up to x12 per symbol
• 8 different Nitro Modifiers w/ 2 displays
• FS w/ sticky Nitro Reels (and safety levels)
• Super FS w/ persistent Max Rows and Both Ways
• Win up to 50,000x your stake

Cons

• 94 % RTP is a dealbreaker for some

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