Comparison

System Ascension vs Sphere TD

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

Head to head
About

System Ascension

An incremental strategy game where you guide a stranded AI to build a planetary engine. Master energy sources, automate resources, and uncover a sci-fi story. The game features beautiful art, full narration, and cross-platform cloud saving.

Highlights
  • Incremental strategy gameplay
  • Resource automation
  • Planetary engine engineering
  • Sci-fi story
  • Cross-platform cloud saving
  • Fully narrated
Features
Read full description

System Ascension: Idle Core is a story-rich, incremental strategy game where you take control of a stranded artificial intelligence arriving on a mysterious planet. Master interlocking power sources, optimize your resource automation, and engineer the ultimate planetary engine. Will you conquer the old world to bring order to the new? Manage an ever-growing global engine of energy generation in an in-depth, multifaceted idle experience. Master planetary forces, from gravity and tidal pulls to the mysteries of quantum energy. Optimize your upgrades, balance your choices, and trigger cascading chain reactions that push your numbers into the stratosphere. Features: - Beautiful and mesmerizing art develops and grows based on your choices - Deep and engaging sci-fi story - Fully narrated by Angela Clark - Cross-platform cloud saving - No ads or in-app purchases of any kind A standalone idle game experience set inside the expansive universe of the isekai LitRPG/Gamelit series Judicator Jane, along with Idle Drops, Mind Construct and Force Escape.

About

Sphere TD

A complex tower defense game where you build and upgrade towers to defend against waves of spheres. Strategize with deep customization, resource management, and research to overcome challenges. Offers extensive replayability with numerous levels and modes.

Highlights
  • Tower and projectile customization
  • 30 base towers with 28+ stats
  • 33 mods with millions of combinations
  • Research and crafting system
  • Tower inventory and energy management
  • 50 hand-crafted levels and endless mode
  • Offline and online play with cloud sync
Read full description

Sphere TD is a tower defense game with one difference: there are no preset towers. You build every tower yourself by combining mods to spam more projectiles. UNIQUE FEATURES - Build & mod every tower. There are no preset towers. - Defend each map with 5 towers. Max them out and spam more projectiles. - Split your shots, bounce, multiply, shock, burn. The build is up to you. - Your base can fly, towers and all. Explore the maps and mine ores. - Research and craft mods. Just don't run out of energy. WHAT IS IN THE GAME - 41 towers, each with its own grid layout and function - 33 mods, each with tiers, MK upgrades, a B-Side function, and 3 perks, for over a million tower builds - 50 hand-crafted maps with three objectives each - Endless mode after map 50, plus map-specific challenges - A research tree, mod crafting, and a trader - Spheres that scale into elites, bosses, armored, shielded, cloaked and flying - Offline play, with cloud sync and leaderboards - Cross platform: mobile and desktop NO NONSENSE No pay to win. No time gates. No paywalls. No ad spam. No loot boxes. Funding the Galatium Academy is appreciated, never required. MESSAGE FROM THE DEV Hi, I'm Alex, a solo developer, and Sphere TD is my first game. If you like tower defense and building your own towers, you should feel right at home. Come discuss tower builds with other friendly cadets on Discord. I am committed to 10 years of support. You want it, I'll make it. Ready to join the Galatium Academy?

Screenshots

System Ascension4 screens
Sphere TD4 screens

Verdict

The call

The clearest difference is price: Sphere TD at Free against System Ascension's $4.99. Sphere TD also leads on review sentiment (100% vs 71%). System Ascension's advantage is in-app purchases (none vs 10) and ads (none vs shown). On update cadence, device support and iOS requirement 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

Sphere TD is free to download; System Ascension costs $4.99 up front. Sphere TD sells 10 one-off in-app purchases. System Ascension asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

System Ascension holds the better App Store score, 4.8 against 4.6. Both are backed by a comparable volume of ratings — 46 and 10 respectively. Written reviews complicate that: 71% of System Ascension's written reviews are positive against 100% of Sphere TD's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

System Ascension ships an update every 5 days, Sphere TD every 3 days. The most recent releases landed on October 28, 2026 and October 30, 2026 respectively.

Scorecard7 real differences · 3 level
System Ascension versus Sphere TD: the parameters behind the verdict, then further details
ParameterSystem AscensionSphere TD
Price$4.99Free — better
Rating4.8 (46 ratings) — better4.6 (10 ratings)
Positive reviews71.4% of reviews100.0% of reviews — better
Number of ratings46 — better10
Update frequencyEvery 5 daysEvery 3 days — better
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details — not scored
Size297 MB316 MB
Age rating12+12+
DeveloperStudio Rouleau IncStandardIssueGames

Customer experience

System Ascension

All ratings42 ratings
Positive92.9%
Neutral4.8%
Negative2.4%
Written reviews7 reviews
Positive71.4%
Neutral0.0%
Negative28.6%

Sphere TD

All ratings10 ratings
Positive90.0%
Neutral0.0%
Negative10.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

System Ascension

No in-app purchases

10 purchases

Sphere TD

One-time10
  • Au Field Ration$4.99
  • Defender Starter Pack$7.99
  • Au Supply Cache$9.99
Show 7 more
  • Galatium Express Token$9.99
  • Galatium Academy Pack$14.99
  • Shadow Broker Vantage$19.99
  • Au Enterprise Fund$24.99
  • Flux Enrichment Grant$24.99
  • Au Strategic Stockpile$49.99
  • Au Global Reserve$99.99

Questions

Is System Ascension free?
System Ascension costs $4.99, with no in-app purchases.
Is Sphere TD free?
Sphere TD is free to download, with in-app purchases available.
Which has better reviews, System Ascension or Sphere TD?
System Ascension is rated higher. System Ascension averages 4.8 out of 5 from 46 ratings, while Sphere TD averages 4.6 from 10 ratings.
Do System Ascension or Sphere TD have ads?
Sphere TD shows ads; System Ascension does not.
Which is updated more often, System Ascension or Sphere TD?
System Ascension ships an update every 5 days, and Sphere TD every 3 days. Most recently, System Ascension was updated on October 28, 2026 and Sphere TD on October 30, 2026.

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