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Undines Deep

Review, Demo Play, Payout, Free Spins & Bonuses

Undine’s Deep is an online slot developed by Endorphina. It has an RTP of 96 per cent and is played on a 5x3 reel grid with 10 active paylines. The game includes ...wild multipliers, free spins with 3x multipliers, and a gamble feature.

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  • Wilds double your winnings when completing combinations
  • Reasonable RTP (above 95 per cent)
  • Interesting and consistent underwater theme
  • Gamble feature is tricky to beat
  • No confirmed variance
  • Only 10 paylines

Undine's Deep review: introduction

Undine is a mythological figure originating in Europe. The stories tell of a water nymph who fell in love with a man and sold her soul to become human and join him on the land; however, she would die should he be unfaithful.

In this underwater adventure slot by Endorphina, you will join Undine as she searches to find a way to join her human love on the land. The 5x3 reel grid provides 10 paylines and is filled with sea life to help this water nymph on her quest.

To win in Undine’s Deep, you will need to land combinations of three+ matching symbols along a payline, starting on the leftmost reel. Undine’s golden fish friend acts as the wild symbol in this slot, capable of helping you on your quest by substituting for any other symbol - excluding the scatter - to help you win bigger and better prizes. He will even double your winnings when he is part of a winning combination!

Undine herself is the scatter symbol in Undine’s Deep. Find three+ of her likeness in any position on the reels to trigger the free spins bonus round in this mythology themed slot. We will look at this round in the bonus features section of this slot review.

In addition to the base and bonus games, Undine’s Deep offers the chance to gamble your winnings in a double-or-nothing gamble feature in which you need to beat the dealer to double your winnings. If you don’t beat the dealer, you lose the lot!

Theme, graphics & soundtrack

For a slot based on the story of a water nymph, it makes sense for Undine’s Deep to be set beneath the seas. This simply designed slot allows you to see sunlight piercing the water, with seaweed growing up the sides of the transparent reels. The symbols in this slot include a variety of sea creatures, such as a starfish and jellyfish, to help you on your quest. The soundtrack is dark and filled with suspense, which is the perfect addition to the storyline of a water nymph who may lose her life.

Undines Deep

Undine's Deep RTP and variance

Undine’s Deep has an RTP of 96 per cent. The variance has not been announced, so you may want to play some Endorphina free slots right here at Slots Temple to get a feel for the potential returns you might achieve in this slot.

How to play Undine’s Deep

As with many other Endorphina slots, the controls in Undine’s Deep are mostly hidden to provide the game with a nice clear screen, uncluttered by icons. To find the controls, read on:

1. When you first load Undine’s Deep, locate the three lines to the left of the reels to uncover your options.

2. To start, click the paytable option to find details about the game, including the paytable, paylines and bonus features.

3. Once you are happy with the rules for the game, head back to the menu and click the bet option to place your wager.

4. If you would like to set up automatic spins, you can choose how many spins you would like and any limits under the autospin heading on the menu.

5. From the menu screen, you will also find the ability to check your stats, alter the sound settings, change the language, or enable left-hand mode. When you are happy with your settings, click the X on the right of the screen to exit.

6. When you are ready to start spinning, look for the transparent spin button on the right-hand side of the reels. Click this once to spin manually or drag the button into the centre of the screen to activate your pre-set autospins.

7. You can keep an eye on your total bet, the number of active paylines and your balance along the bottom of the screen.

Bet sizes & paytable

Wagers are placed in two parts in Undine’s Deep. First, select your desired denomination from 0.01 to 1.00; next, place your bet from 1 to 10. You can also alter the number of active paylines you want to play from the betting screen.

Assuming you choose to play with all 10 paylines active, this gives you a betting range of 0.10 to 100.00 per spin, which should appeal to most players.

The top prizes available in Undine’s Deep occur when you line up five matching symbols along a payline. Using a wild substitution can double your winnings, and you can hit a 3x multiplier in the bonus game.

Excluding any multipliers or bonuses, the top prizes for each symbol are as follows:

- Starfish: 7,500
- Sea urchin: 7,500
- Jellyfish: 4,000
- Seahorse: 2,500
- Shell: 2,500
- Ace, king: 1,250
- Queen, jack, ten, nine: 1,000

The wild will also pay out for matches along a payline, with a top prizes of 90,000. Line up five scatters along a payline for prizes up to 50,000.

Undine’s Deep bonus features: free spins

The main bonus feature in Undine’s Deep is the free spins bonus round, which is triggered by landing three+ scatters in any position. During this round, every win will be awarded a 3x multiplier. You will be given 15 free spins with the ability to trigger a further 15 spins with three+ more scatters.


Overall, we really enjoyed Undine’s Deep. It is fairly unusual to find European mythology making it into the world of online slots and we thought Endorphina did a great job of bringing this story to life. We are still not completely sold on the control layout Endorphina uses, but the graphics, soundtrack and winning potential certainly make up for it! We were particularly impressed by the prizes available when wilds come into play in this slot, and the 3x multiplier in the free spins round gave us plenty to be happy about.

If you enjoyed Undine’s Deep and fancy another underwater adventure, why not check out Mermaids Millions by Microgaming?


Disclaimer: Undines Deep trademark / license is owned by Endorphina. This site is not endorsed by Endorphina.

Slot Data
Slot Name: Undines Deep
Software: Endorphina
RTP: 96%
Paylines: 10
Reels: 5
Min Bet (all lines covered): £0.01 (GBP)
Max Bet: £100 (GBP)
Top Win: 90000
Features: Wild Symbol, Multiplier, Free Spins, 5 Reels
UK Available in UK? No. :maker does not have a UKGC license and cannot offer their games at UK licensed casinos.


What is the RTP of Undine’s Deep?

The RTP is 96 per cent.

How volatile is Undine’s Deep?

The volatility has not been announced.

What is the biggest win available on Undine’s Deep?

The biggest win is 90,000 for landing five wilds on a payline.

Does Undine’s Deep have a free spins bonus round?

Yes, the free spins bonus round is triggered by landing 3+ scatter symbols in any position.

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