

Blackhole is an online slot from GRIMFORGE with an RTP of 94.97176702823289%.
Page updated July 2026
Blackhole is a slot from developer GRIMFORGE, confirmed with an RTP of 95%, though detailed reel, payline and volatility information hasn't been published yet for this title. The name points clearly toward a cosmic, space-horror theme — expect swirling void imagery, distant stars being pulled into darkness, and a symbol set that likely leans into astronomical and sci-fi iconography rather than anything grounded or familiar.
GRIMFORGE's naming style suggests a developer leaning into darker, more intense visual territory, and a game called Blackhole gives plenty of scope for dramatic lighting effects, deep-space soundscapes and a genuinely tense atmosphere as the reels spin. It's a theme that stands out from the crowded pack of fruit machines, mythology slots and animal-themed bison games covered elsewhere in this roundup, offering something visually distinct for players after a change of scenery.
A 95% RTP sits a shade below the 96% figure many players treat as the standard benchmark for a fair slot, though it remains a common and entirely reasonable return rate across a large portion of the current market. Over a sufficiently large number of spins, Blackhole is designed to pay back £95 for every £100 wagered, with the house holding a 5% edge. It's worth factoring that into your expectations if you're comparing Blackhole directly against some of the higher-RTP titles featured elsewhere on the site.
GRIMFORGE hasn't published an official volatility rating for Blackhole yet, so it's worth treating your opening sessions as a chance to scout the game's natural rhythm. Playing smaller stakes for the first run of spins should give a reasonable sense of how often the game pays and roughly how big those returns tend to be, before scaling your bet size up or down.
No maximum win multiplier or minimum/maximum bet range has been published for Blackhole at this stage. Checking the in-game paytable and info screen once the title is live remains the most reliable way to confirm these figures, since they're often finalised closer to a full release.
Blackhole's cosmic theme and GRIMFORGE's clearly dark, intense visual style make it a distinctive addition to the slot market, even with a workmanlike 95% RTP and several details still pending confirmation. Once it's available, spin through the free demo at johnessyslots to get a sense of the atmosphere and pacing before deciding whether to commit real money to it.
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Blackhole has an RTP (return to player) of 94.97176702823289%. RTP is the theoretical percentage of total stakes a slot returns to players over a very large number of spins, as published by GRIMFORGE — individual sessions can land far above or below it.
Blackhole is developed by GRIMFORGE.
Verified Data via Johnessy AI

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