Nitropolis 5

A randomly chosen symbol type receives Holding Cells. If that type participates in a win, its symbols lock in together with Bonus symbols and Nitro Multipliers while a respin expands the main grid.

The sequence continues while more symbols of the chosen type contribute to the Holding Cell win, or another Holding Cell feature triggers. A further trigger can add another selected symbol type. When the sequence ends, locked symbols pay if they form a win and normal play resumes.

Cells which do not contribute to a Holding Cell win are released at the end of a spin or before a respin. Nitro Match, Gritty Kitty, Pug Thugs and Rogue Rats do not affect the symbols or Nitro Reels already selected for this feature. Those exclusions explain why an apparently helpful Booster effect may leave a held area untouched.

The three flippers above the main grid can award effects before the reels stop, after they stop, or after win evaluation. Six effects act on the main reels and five act on Nitro Reels. Their different timing matters: a Respin waits for ordinary wins to finish, whereas Max Rows expands the board when it lands.

Nitro Wild, Nitro Upgrade and Nitro Match can wait above their relevant reels if there is no eligible Nitro Reel underneath. They remain pending until they can be used or the game round ends. A Super Bonus symbol is excluded from all three; Nitro Wild also excludes multiplier reels.

Three or more Bonus symbols trigger Free Spins. A Super Bonus symbol among the triggering symbols starts the Super Bonus instead. It can appear only in a Nitro Reel and counts once, even when that reel has a larger size indicator.

All Nitro Reels remain in play during Free Spins. The normal bonus starts with a safety level of four rows. Each winning free spin raises that starting level by one row; stacked Nitro Reels can raise it further. The level cannot exceed eight rows, and the next free spin begins at the new level.

Ordinary avalanches expand a particular sequence. The safety level changes the starting height of later free spins. Keeping those two ideas separate makes the bonus easier to follow: a taller next spin reflects retained progress, not necessarily a new expansion award.

Three or more Bonus symbols during the bonus award more spins using the same schedule as entry. A Super Bonus symbol in that trigger upgrades the feature. The bonus ends when no spins remain or the win cap is reached.

The Super Bonus starts with Max Rows and Both Ways active, and NPD Holding Cells trigger on every free spin. It combines a fully expanded board, wins evaluated from either edge and the possibility of a separate locking-and-respin sequence.

In the normal bonus, Max Rows and Both Ways can activate later and then remain for the rest of that bonus. Features active before ordinary bonus entry are deactivated on entry; the Super Bonus has its own upgraded starting state. This is a structural change, not simply an extra allocation of free spins.

Three Boss Battle coins in the Nitro Booster trigger the battle after the current spin or free spin. The normal reels are temporarily replaced by a 7×8 grid containing empty positions, coin values and a possible MAX WIN position.

You receive three shots. Hitting a coin collects it, empties that position and resets the remaining shots to three. The battle ends when no shots remain or MAX WIN is awarded. Collected values are multiplied by the current bet, after which the ordinary reels return and play continues.

This trigger uses Boss Battle coins in the Booster, not the Bonus symbols on the main grid. It is an independent route through the game; seeing a Boss Battle coin does not count towards the three-symbol Free Spins trigger.

ELK documents five paid entry modes. Its game page gives a 3× bet Bonus Hunt entry and a 500× bet Super Bonus entry; the saved rules name the three intermediate modes but leave their prices as configuration placeholders. Those missing prices are not filled from a different title or a screenshot of a different mode.

X-iter can be activated only from the base game, and availability depends on the operator and market. A boosted chance or guaranteed feature changes the entry conditions and stake exposure; it does not guarantee a profitable result.

ELK lists a maximum potential of 50,000× bet. The rules end the game round immediately when its win cap is reached and pay the collected amount. A headline maximum does not establish how frequently the cap, a bonus or any individual Booster effect occurs.

The retained general-rules file contains unresolved placeholders for RTP, minimum and maximum stakes and maximum-win probability. Check those values in the game actually offered by the operator. A rules-document update date is also not a release date for the slot.

Start with the row count and the contents of each Nitro Reel. A big symbol, a cluster of small symbols inside a reel and a Nitro Multiplier may occupy similar space while contributing differently to ways and payout.

Next check whether a feature is pending above a reel, active for the current round, or retained into later free spins. The same visible feature name can matter at different times. In particular, keep Holding Cell collection, ordinary avalanche collection and Boss Battle collection separate.

The game suits players who enjoy several interacting feature systems and persistent bonus progress. It asks for more attention than a simple fixed-line slot. A high maximum and many named features are not evidence of a particular volatility category or better value.