Nitropolis 2

Editor's rating:
Published: May 11, 2021

Nitropolis 2 Slot Review (ELK Studios)

Nitropolis, one of the most intense slots of 2020, has been given a bonus buy and reel booster treatment.

ELK Studios’ Nitropolis 2 is a fast-paced slot with a mind-boggling 191,102,976 possible ways to win. That is more than twice as much as the original game and way more than most other slot games (combined). That is now possible thanks to the new Nitro Booster reel with 8 different reel upgrades, which make reel drops even more dynamic. And those who have access can now buy the free spins bonus outright, among four other features that have been made available for instant activation through the studio’s exclusive X-iter bets. But does this excessiveness make it any better?

Nitropolis 2 has been available for play at licensed and regulated ELK Studios slot sites like Mr Green from 4 May 2021.

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Winning Re-spins

Nitropolis 2 looks quite similar to the first game in that it also has a Wild symbol and 12 regular symbols which can also appear stacked. Likewise, whenever you win, the winning symbols will always re-spin for a second try and so on.

The main difference is that the payouts have been diluted quite significantly to accommodate the new format with the Nitro Booster.

Nitro Reels

Similar to Nolimit City’s xWays mechanic, which has been very successful in slots like Punk Rocker and San Quentin, Nitro Reels make each reel spin less predictive and potentially more rewarding. Instead of 4 symbols on a reel, a Nitro Reel covers 2 symbol places but can contain 4, 6, 8, 10 or 12 payout symbols each. That means two Nitro Reels in a single column can contain up to 22 symbols per reel!

When translated into pay-lines, Nitropolis 2 pays in 4,096 different ways, but with the addition of Nitro Reels, ways to win can increase exponentially to a maximum of 191,102,976! This is where Nitro Booster comes into play.

Nitro Booster

Featuring all-new Nitro Boost reel at the top.

Nitro Booster is an additional bar at the top of the reels that contains 8 different boost features as well as Bonus symbols. It has appeared in a similar form also in ELK’s previous releases like Ice Wolf, and Hit It Big.

The idea is simple, land one of the following Nitro Boosters above any of the 6 reels to activate it on the same reel or across the entire screen:

  • All Wild – All sticky and landing Nitro Reels will contain wild symbols.
  • All Premium – All Nitro Reels will contain high-value symbols.
  • All Match – All Nitro Reels will match up with a symbol on the reel to the left.
  • Nitro Wild – Nitro Reels in the same column will contain wild symbols. Guarantees all wilds if All Match and All Premium also land in the Nitro Booster.
  • Nitro Upgrade – Nitro Reels in the same column are upgraded and add additional symbols to the Nitro Reels.
  • Nitro Match – All Nitro Reels will match up with a symbol on the reel to the left.
  • Both Ways – win both ways, remains sticky until there are no more respins or wins.
  • Respin – respins all reels when there are no more wins.

Note that the first 6 will affect only the Nitro Reels, and the last 2 the main reels. As such, many of them won’t work without the Nitro Reels, unless there was a way to have more of them at once!

Bonus Game

Line up those Nitro Reels in Free Spins for mega wins!

Get 3 or more bonus symbols (also appear in the Nitro Booster) to trigger the free spins bonus game with 10, 15, 20 or 25 free spins, respectively. The bonus can be re-triggered the same way. Also, like the first version of the game, during free games, all Nitro Reels will lock in place for the remaining free spins.

The beauty of Nitropolis 2 is that during the free spins, when Nitro Reels are sticky, Nitro Booster offers much more potential over the base game. However, it can take quite a while to get through to the bonus, including all the win re-spin action that happens every few spins at a 20% hit frequency. There is one shortcut that some players will be allowed to use though.


X-iter is ELK Studio’s enhanced version of Bonus Buy which first appeared with the release of Bompers. It allows you to choose from and buy 5 different game modes for x-times your stake:

  • 5x – guarantees a winning spin.
  • 25x – guarantees 3 with a full Nitro Booster on every spin.
  • 100x – triggers 10 free spins with three bonus symbols.
  • 200x – triggers 15 free spins with four bonus symbols.
  • 500x – triggers 10 free spins with guaranteed 12 Nitro Reels!

Given the 0.20—100 credit bet ranges, this means that the X-iter features can cost you between 1 and 50,000 credits a pop! Casino-specific restrictions may apply though. Keep in mind that while the cost does give some indication of an average win, it feels a lot more volatile and unpredictable compared to the Nolimit City slots.



Editor's rating:

Nitropolis 2 continues with the high-octane vibe and award-winning bonus craze that the first game brought about in November 2020. This will still make it a tempting choice for players who like Punk Rocker xWays. With all the Nitro features, the sequel appears to be even more technically complex, which must have been a tough nut to crack for the developer.

Based on my experience, the new features are fun to have and complement the first title, but I wish this also expressed in some other way like a higher maximum win or more sizable prizes in the base game, which it doesn’t. Instead, the RTP has gone down from 96.10% to 95%, which can be a tough pill to swallow for some punters and not a direction that I endorse game providers to follow. On the upside, the addition of X-iter makes this sci-fi slot significantly more intriguing, especially that the high-end free spin bonuses are otherwise so rare to come up naturally.

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