Comparison

Once Upon a Galaxy vs Reactor

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Once Upon a Galaxy

Embark on a fantasy card battling adventure where you draft unique captains and their friends to complete quests. Choose your path with diverse characters and strategic gameplay. Experience a game free of ads and AI art, focusing on player choice and engaging battles.

Highlights
  • Fantasy card battling
  • Captain drafting
  • Quest completion
  • Strategic gameplay
  • No AI artwork
  • Asynchronous play
Features
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Galaxy is FREE to play, has NO ADS, uses NO AI artwork. Will you choose Dorothy as your captain and help her and friends on their journey to complete their quests? Or Dragonmother and discover what will hatch from her dragon egg? Or maybe Indiana Clones, who will "clone" your best three treasures? It's all up to you!

About

Reactor

Features
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Twelve turret slots ring a glowing reactor Core. The swarm descends from three lanes — dead center and both flanks — so a lopsided ring gets punished. Drag two matching turrets together to merge them a tier higher, place them where their roles line up, and hold. Reactor: Core Siege is a merge tower-defense roguelite you actually play — no auto-battler doing the work, no timer holding your progress hostage. SKIP THE GRIND — NEVER THE RANK Most strategy games sell you power and call it fair. This one splits the two cleanly. Your own runs are yours to speed up however you like. But the Daily Descent is wallet-immune: every player gets the identical date-seeded board, it is 100% ad-free, and nothing you buy can touch it. Your result there is your merges, your placement, and your Overclock timing. Nothing else. Money can buy your time back. It can never buy your rank. New in 1.1: a daily Game Center leaderboard where everyone climbs that exact same board. THE LOOP Waves descend toward the Core. Merge turrets from tier 1 up to tier 6, mix the three roles — Striker, Support, Splash — around the ring, and slam Overclock, a burst cooldown, on the right beat. Between waves you draft one of three cards: a new turret, a relic, or a lane modifier. Clear, draft, push deeper. Run it at 1x, or flip to 2x when you know what you're doing. WHAT'S IN IT - 12 turret types across a T1-T6 merge ramp — rockets, plasma, lasers - 3 turret roles: Striker, Support, Splash - 10 relics that bend the rules - 6 lane-modifier cards - 8 enemy types, from Scuttlers to Void Elites - The Warden Core — a boss every 10 waves with three telegraphed attacks: Core Slam, Ring Sweep, Static Snare - A 30-node, two-track prestige tree — 10 session nodes plus 20 prestige nodes - An 8-rung ascension ladder, Warm-Up through Impervious - A daily Game Center leaderboard + achievements — the ranked, wallet-immune surface - A blueprint collection to complete - The date-seeded Daily Descent, with a streak worth protecting EVERY RUN CAN PLAY DIFFERENTLY The prestige tree doesn't just hand you bigger numbers. Most of the prestige track unlocks new turrets, new relics, and new lane modifiers that widen your draft pool — so a run weeks in draws from a deck your first run never saw. HONEST PRICING — NO SUBSCRIPTION The whole game is free, and there is no subscription. Optional rewarded ads speed up your own progress if you choose to watch one. Prefer none at all? Ad-Free Forever is $3.99 once and it's yours for good — not a rental. There's also a one-time Starter Pack ($0.99) and a Spark Pack ($4.99) if you'd rather skip ahead in your own sandbox. No loot boxes. No spin-to-win. No countdown bundles. And none of it reaches the Daily. PRIVATE AND OFFLINE Plays fully offline. No account, no sign-in, no server watching your runs. Your progress lives on your device. Merge the ring. Time the Overclock. See how deep you can hold. — Questions or feedback? Email dark2torch@gmail.com — we usually reply within a day or two. Privacy Policy: https://moathothman.github.io/ExploringIdeas-legal/coresiege/privacy.html Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Once Upon a Galaxy4 screens
Reactor4 screens

Verdict

The call

The clearest difference is ads: Once Upon a Galaxy at none against Reactor's shown. Once Upon a Galaxy also leads on device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price, update cadence and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Once Upon a Galaxy sells 9 one-off in-app purchases and Reactor sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Once Upon a Galaxy ships an update fortnightly, Reactor every 2 weeks. The most recent releases landed on November 12, 2026 and October 31, 2026 respectively.

Scorecard3 real differences · 7 level
Once Upon a Galaxy versus Reactor: the parameters behind the verdict, then further details
ParameterOnce Upon a GalaxyReactor
PriceFreeFree
Rating4.8 (1.4K ratings) — better—
Positive reviews83.4% of reviews—
Number of ratings1.4K — better—
Update frequencyFortnightlyEvery 2 weeks — better
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS15.0 — better17.0
Further details — not scored
Size195 MB19 MB
Age rating9+9+
DeveloperMillion Dreams GamesMoaath Othman

Bugs and requests

Once Upon a Galaxy

Reported bugs

3 issues
  • Black screen on startup
  • Infinite loading issues
  • Progression loss after updates

Requested features

5 requests
  • More hero/card variety
  • Improved tutorial and learning tools
  • Offline/save progress mode
  • Cosmetic/non-gameplay monetization
  • Competitive/ranked modes

Reactor

Not enough reviews yet to summarise bugs or requests.

In-app purchases

9 purchases

Once Upon a Galaxy

One-time9
  • Welcome Bundle2 variants$4.99
  • 500 Gems$4.99
  • October 2026 Galaxy Pass$9.99
Show 6 more
  • March 2026 Galaxy Pass$9.99
  • December Galaxy Pass$9.99
  • October 2025 Galaxy Pass$9.99
  • September 2025 Galaxy Pass$9.99
  • 1,100 Gems$9.99
  • 2,300 Gems$19.99
3 purchases

Reactor

One-time3
  • Starter Pack$0.99
  • Ad-Free Forever$3.99
  • Spark Pack$4.99

Questions

Is Once Upon a Galaxy free?
Once Upon a Galaxy is free to download, with in-app purchases available.
Is Reactor free?
Reactor is free to download, with in-app purchases available.
Do Once Upon a Galaxy or Reactor have ads?
Reactor shows ads; Once Upon a Galaxy does not.
Which is updated more often, Once Upon a Galaxy or Reactor?
Once Upon a Galaxy ships an update fortnightly, and Reactor every 2 weeks. Most recently, Once Upon a Galaxy was updated on November 12, 2026 and Reactor on October 31, 2026.

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