Thinking about giving Undine's Deep a spin? We tested it thoroughly so you know what to expect. Built by Endorphina, it lands as a title with very high variance and a return-to-player rate of 96.04%. It's given an engaging visual treatment and plays out on 40 paylines across 5 reels. Originally released in 2018, it has aged well. The maximum win sits at 900,000x, so there's serious upside on the table. Here's how it stacks up.
Written by Sarah Mitchell · Last updated: March 2026
Undine's Deep comes to us from Endorphina, wrapped in polished, characterful visuals and powered by 40 paylines across 5 reels. The result is very high variance paired with an RTP of 96.04%.
Where Undine's Deep earns its keep is the feature set. Look out for scatter symbols that unlock free spins and extra bonus rounds. With very high variance, this one is aimed at players who can ride out the swings for the top wins. On balance, Undine's Deep is a dependable option worth a few spins in the demo first.
The RTP of 96.04% is right around the industry average of ~96%. This represents a fair return that's in line with what most modern slots offer.
Very high volatility delivers the most extreme payout profile — long dry spells punctuated by potentially massive wins. Only recommended for experienced players with substantial bankrolls and high risk tolerance.
About 1 in 3 spins results in a win. This is a moderate hit frequency that balances win frequency with payout size.
Undine's Deep features scatter symbols that can trigger free spins rounds. Landing the required number of scatter symbols anywhere on the reels activates the free spins feature, giving you extra chances to win without additional bets. During free spins, special modifiers may apply to boost your winning potential.
3.0 / 5 — Good
Undine's Deep by Endorphina is a solid offering that delivers good entertainment value. The 96.04% RTP combined with very high volatility creates a well-balanced gaming experience.