ELK Studios’ latest cinematic slot sequel has seen yet another return of its band of oil-drilling animals in Nitropolis 4.
Nitropolis 4 is a 6×4 reel slot with 4.096 base game payways and a maximum win of up to x50,000 the player’s stake.
94 per cent
Low value symbols come in the form of playing card royals, from Jack through to Ace. If the right amount of matching combinations land on a single spin, these symbols can offer between x0.1 and x0.3 the player’s bet.
Next up, each drilling squad animal’s own emblem represents the medium value symbols, with rogue rats, pug thugs, gritty kitties and dirty dawgs. These symbols can offer between x0.15 and x1, depending on the amount of paying combinations that land on one spin.
Each drilling squad member makes up the high value symbols, with rats, pugs, cats and Dobermans offering between x0.5 and x3.
Wild text mines are also available, substituting for all symbols other than the bonus and super bonus symbols.
Bonus text scatters can drop into play, triggering eight, 12, 16 or 20 free spins in the bonus game mode if three, four, five or six bonus symbols land on the same spin.
If one of these triggering bonus symbols is a super bonus text symbol, the super bonus game mode will be awarded.
This game uses cascading wins, meaning that symbols in a winning combination will disappear after providing their payout, making way for new symbols to drop in and increase the win potential.
Symbols can drop in with nitro reel enhancements. Nitro reels cover two cells in the same reel but can act as between three and 12 standard symbols to increase the spin’s payways.
Additionally, large nitro symbols can drop into play, acting as either two, three, four, five or six 2×2-sized symbols.
Nitro multipliers can also appear, applying between x4 and x12 multipliers to any wins on the spin they land on.
Mega symbols are available, causing standard paytable symbols to appear in 2×2 and 3×3 sizes.
Throughout the base and bonus game modes, the nitro booster sits above the reels, randomly allocating one of eight special features on selected spins.
The redrop feature can be activated, triggering a free respin where all bonus, wild and nitro symbols stay on the reels.
Another feature is the both ways enhancement, causing payways to run from right to left and from left to right.
The max rows feature will cause the reel set to expand to eight symbols high, while the garbage collect feature causes one randomly selected symbol to be removed from the reel set while others drop in.
Furthermore, nitro appear causes nitro symbols to be placed onto the reels and nitro wild causes an existing nitro symbol to be replaced with duplicate wilds.
Nitro upgrade can also be triggered, increasing the number of duplicates in an already-present nitro symbol.
Finally, nitro match allows a present nitro symbol to be replaced by a symbol adjacent to its reel, increasing the nitro symbol’s win potential.
During the free spins game mode, all nitro symbols stay sticky on the reels and the reel set expands with each winning free spin.
The difference between the bonus and super bonus game modes is that the super bonus mode starts with the maximum reel set size of 6×8.
To try out the Nitropolis 4 demo, click here.