Project Rhombus — cheap CD keys, compare prices
Is it worth buying?
Reviews are excellent (Steam 93%) · The price is at or near the lowest we've tracked — a good time to buy
Buy · Steam €0.81
About the game
Project Rhombus is a free-to-play rhythm-based casual action game from SEROSOO that pairs exciting electronic music with a stylish flat design. Players hold on as long as possible, blocking incoming arrows that move to the beat.
Did you know?
Project Rhombus is a Free to Play release published by PsychoFlux Entertainment.
Best price today
€0.81
· · check “Region” on the seller’s page
Steam · Official store · Steam
Global key · check “Region” on the seller’s page
You pay Steam directly · same price as on their site
Notify me when it drops below €0.73
- On Steam
- €0.81
- all-time low
- €0.812 Oct
- Average low, 5 mo.
- €1.03
The cheapest Project Rhombus key right now costs €0.81 at Steam. (Prices as of )
Offers 1 · PC · from €0.81
Prices as of
No offers match these filters — try widening them.
Listed seller price shown — payment fees may vary by method.
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Lowest official since we started tracking (Aug 2026)
€0.81
Oct 2026
Monthly price lows
| Month | Lowest official | Lowest keyshop |
|---|---|---|
| Oct 2026 | €0.81 | — |
| Sept 2026 | €1.09 | — |
| Aug 2026 | €1.09 | — |
| Jul 2026 | €1.09 | — |
| Jun 2026 | €1.09 | — |
Lowest in-stock price per month from our price history; the current month is the low so far.
How to activate your key
- Steam key — open the Steam client → Games → Activate a Product on Steam → enter the key. Stores with this activation: Steam
System requirements
| Minimum | |
|---|---|
| OS | Windows Vista / 7 |
| Processor | 1 GHz 32-bit or 64-bit processor |
| Memory | 1 GB RAM |
| Graphics | CPU-integrated or on-board graphics |
| DirectX | Version 11 |
| Storage | 120 MB available space |
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About this game — FAQ
Can Project Rhombus be played single-player?
Yes, Project Rhombus is a single-player game.
Does Project Rhombus support a controller/gamepad?
Yes, Project Rhombus has full controller support.
What languages does Project Rhombus support?
Project Rhombus is available in: English.
Does Project Rhombus use Steam Cloud saves?
Yes, Project Rhombus uses Steam Cloud, so your saves sync across devices.
FAQ
Where is the cheapest place to buy a Project Rhombus key?
The cheapest Project Rhombus key is currently sold by Steam for €0.81. The lowest price we have ever recorded for this game: €0.81.
How much does Project Rhombus cost?
Project Rhombus currently costs from €0.81 — the cheapest offer across the stores we track.
Is Steam an official store or a keyshop?
Steam is an official store — keys come directly from the publisher or an authorized distributor.
Are keys from these stores legal?
Buying is legal — keys come from the grey market, so a small deactivation risk exists. So before paying, check the seller's buyer protection.
Which key region should I pick?
Global activates everywhere. Regional keys (Europe, North America, RU-CIS) only work on accounts from that region — use the Region filter to match your account.
What is an activation platform?
The service where the key activates — Steam, GOG, Epic or the publisher's platform. A key for one platform won't work on another, hence the separate filter.
What's the difference between editions?
Standard is the base game; Deluxe usually adds an expansion or bonus content. The edition filter shows exactly that variant, with no mixed prices.