Quick answer: Compute the denominator from the actual registry of all collectibles, audit for unreachable or duplicate-ID items, and round only for display so a full run shows exactly 100%.
A completionist who clears everything and still sees 99% will assume your game is broken. Make the total an authoritative count of every trackable item and verify each one is actually reachable.
How to fix it
1. Derive the total from a registry
Build the denominator by counting every collectible, map cell, and ability in a single data source instead of a hardcoded constant. A constant drifts out of sync the moment you add or remove content.
2. Audit for unreachable items
A collectible behind a wall with no key, or one that shares an ID with another, makes 100% impossible. Run a tool that lists every tracked item and confirm each can be obtained.
3. Round only at display time
Keep the underlying ratio exact and round for the UI. If you store a rounded value you can accumulate error; computing collected == total separately guarantees the 100% flag is honest.
Catching the ones you can't reproduce
The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.
Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.
This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.
A crash you can name from its stack trace is a crash you can usually fix in minutes.