Each figure below is the percentage Steam displays for one named achievement. The games are an illustrative selection across several genres, not a random sample of Steam games. The milestones differ, so the table is useful for examining definitions as well as numbers.
The milestone rates
| Game | Milestone used | Unlock rate | What it marks |
|---|---|---|---|
| Hades | Is There No Escape? | 46.7% | Clear one escape attempt, not the end of every story thread. |
| Celeste | Celeste | 34.6% | Climb Celeste Mountain, the main ascent. |
| Portal 2 | Lunacy | 34.1% | Reach the single-player campaign ending. |
| Terraria | Champion of Terraria | 24.7% | Defeat the Moon Lord; a final-boss milestone in a sandbox game. |
| Hollow Knight | The Hollow Knight | 24.5% | One ending route: defeat the Hollow Knight and become the Vessel. |
| Cuphead | Souls Saved | 17.6% | Complete the game on Normal difficulty. |
Source: each linked Steam global achievements page. Steam rounds the displayed rates to one decimal place. The figures were viewed on October 18, 2026; a search or page cache may lag Steam's live values.
What do these percentages mean?
Steam labels these figures as the percentage of players who unlocked an achievement. They are achievement unlock rates, not a count of purchasers, an estimate of hours played, or a survey of why people stopped playing. Steam does not publish the underlying player count beside each percentage on these pages.
“Completion” changes meaning by game. Hades tracks a first successful run. Terraria has no single campaign ending in the same sense as Portal 2. Hollow Knight has multiple ending routes, and the row above measures only the named route. Cuphead's selected achievement specifies Normal difficulty. A higher rate here does not prove a game is easier or better.
Method and limitations
We selected six well-known Steam games with a public achievement that marks a clear major milestone. For each one, we recorded Steam's displayed global percentage and the achievement name, then classified what that milestone represents. We excluded games with no suitably clear milestone. The linked source pages and the source table (CSV) make the comparison reproducible.
The selection is illustrative and cannot establish an average completion rate for Steam, a genre, or a release year. The six percentages have different player populations and milestone definitions; we therefore do not average them. Achievement systems can also change after release, and unlocking an achievement is not guaranteed to capture every playthrough. Recheck Steam before quoting a current rate.
How to use the data when choosing a game
Start with the milestone description, then read the percentage. A first escape, a story ending, and a final boss answer different questions. If you're choosing a game for a satisfying challenge, also consider its retry structure and your preferred session length. Our precision platformer guide compares that side of the experience.
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All six rates and achievement labels come from the Steam pages linked in the table. Steam's ISteamUserStats documentation describes its global achievement percentage data. Last checked: October 18, 2026. Refresh the table when a source game changes its achievements or before citing it as current.