The critical difference between a Category B and a Category S score in FORENSIC - M.E. Protocol is the margin for error: there is none for an S-rank. A Category B score means you correctly solved the case but missed secondary evidence or made minor procedural mistakes. A Category S score is awarded only for absolute perfection: finding 100% of all evidence, committing zero procedural fouls like cross-contamination, and achieving flawless accuracy in your final deductions.
Think of it as competence versus mastery. A 'B' makes you a good investigator; an 'S' proves you're an elite forensic analyst who leaves no trace and misses no detail. For players hunting the coveted "Forensic master" achievement, understanding this distinction is the entire game.
What Defines Your Case Score?
At the end of each of the game's nine cases, your performance is graded on a scale from F to S. This grade isn't arbitrary; it's calculated based on a few core pillars of your investigation. While the exact formula is hidden, gameplay reveals three primary components: Observation, Deduction, and an unspoken third metric we'll call Protocol Adherence.
- Observation Score: This is the most heavily weighted component, accounting for roughly 78% of your total score. It measures your ability to find and document every single piece of evidence at the scene. This doesn't just mean the obvious murder weapon or bloodstain; it includes microscopic fibers, faint scuff marks visible only via drone, and latent prints you must meticulously dust for. Every piece of evidence must also be photographed correctly to count towards this score.
- Deduction Score: This component makes up the remaining 22% and is tested during the final summary phase. After collecting all evidence, you must review your findings and mark only the items that are key to solving the case. Successfully identifying the crucial clues while ignoring the red herrings is what determines your Deduction score.
- Protocol Adherence: This is the invisible gatekeeper for an S-rank. The game constantly monitors your procedure. Did you walk over the chalk outline and contaminate the scene with your footprints? Did you forget to barcode a sample vial before putting it in the centrifuge? Did you use a dirty swab? Each of these errors adds a demerit that can lock you out of an S-rank, even if your Observation and Deduction are otherwise perfect.
The Path to Category B: The Competent Investigator
A Category B score is the standard "good" ending for a case. It signifies that you successfully understood the crime, identified the primary evidence, and came to the correct conclusion about what happened. Most first-time playthroughs of a case will likely end in a B or lower, and for many achievements, a B-rank is all that's required.
You can typically earn a Category B by:
- Finding all primary pieces of evidence (e.g., the body, the weapon, major bloodstains).
- Correctly analyzing the most important samples.
- Making the right final conclusion in the summary, even if you missed a few supporting clues.
A B-rank explicitly means you made mistakes. Perhaps you missed a secondary clue, like the hidden fiber in the "Introduction" case that requires the ground robot. Maybe you failed to photograph a few items or made a minor error in the final evidence selection. It's a respectable score, but it leaves room for improvement.
Comic grid showing the steps for a Category B score, such as finding the wrench.
The Ascent to Category S: The Master Analyst
Achieving a Category S rank transforms FORENSIC - M.E. Protocol from a detective game into a meticulous, unforgiving puzzle. It demands a flawless performance across all three scoring pillars. You cannot miss a single thing or make a single mistake. This is a test of patience and methodical precision, not just logic.
100% Observation: Leaving No Stone Unturned
This is the most demanding part of an S-rank run. You must find everything. In a game with no objective markers, this requires a systematic search of every square inch of the crime scene with every tool at your disposal.
- Master Your Tools: An S-rank is often impossible without the advanced tools. The aerial drone is essential for spotting clues in high places, like the window scuff in the tutorial. The ground robot is needed for evidence in low-clearance areas. Your UV flashlight and luminol spray will reveal biological traces invisible to the naked eye. You must learn their functions and use them everywhere.
- Photograph Everything: Before you interact with, mark, or collect any piece of evidence, you must photograph it. A melody will chime to confirm a successful photo. If you collect an item before photographing it, you can lock yourself out of a perfect Observation score for that run.
- The "Introduction" Case Example: The perfect illustration of this principle is the tutorial case. To get an S, you must find four key things: the wrench, the bloodstain, the window scuff, and a hidden fiber under some pallets. Missing that single fiber, which is only accessible via the ground robot, will cap your maximum score at an 'A' rank, no matter how perfectly you perform every other action.
Infographic showing hidden evidence locations like the 'Hidden Fiber' in the tutorial case.
100% Protocol Adherence: The Zero-Contamination Rule
This is where most aspiring S-rank investigators fail. FORENSIC - M.E. Protocol is brutally realistic about procedure. One misstep can invalidate your entire effort. Adherence is not optional; it is paramount.
- Mind Your Step: The game tracks your footprints. Walking through a bloodstain or over the primary crime scene area will instantly contaminate it, voiding your S-rank potential. Use your drones and robots to survey the scene before committing to a path.
- Handle Evidence Correctly: Every action must be deliberate. When you take a fluid sample with a sterile cotton swab, you must immediately place it in a vial and barcode that vial for the analysis machine. Failure to do so results in an 'Unidentified Sample' error and a failed run. When dusting for prints, you must use the brush first, then the adhesive tape.
- Use the Markers: Before photographing many types of evidence, the game expects you to place an evidence marker next to it. Forgetting this step can invalidate the photograph in the game's scoring logic. You only have a limited number of markers, so place them wisely.
Poster stating 'PROTOCOL IS PARAMOUNT' to emphasize the zero-contamination rule.
100% Deduction: Weeding Out the Red Herrings
After hours of meticulous fieldwork, the final step is the case summary. This is where you present your findings. For an S-rank, your report must be as clean as your crime scene.
To achieve this, you must open your tablet, go to the summary/resolve folder, and select only the pieces of evidence that are directly relevant to solving the case. The game intentionally includes red herrings—clues that seem important but ultimately lead nowhere. A fingerprint might match someone in the database who had a valid alibi, for instance. Selecting that fingerprint as key evidence is a mistake.
For a Category S, you must mark all correct evidence and avoid marking any false evidence. A Category B might be awarded if you correctly identify the culprit but mistakenly flag an irrelevant clue. For an S, there is no such leeway.
Side-by-Side: Category B vs. Category S Requirements
To put it all together, here is a direct comparison of what is generally required for each rank.
| Metric | Category B (Competent) | Category S (Perfection) |
|---|---|---|
| Evidence Found | All primary evidence; may miss 1-2 secondary items. | 100% of all evidence, including hidden/tool-gated items. |
| Photos Taken | Most key evidence photographed; may have misses. | All required evidence photographed correctly before interaction. |
| Contamination Events | 1-2 minor events may be tolerated (e.g., a misstep). | Zero. Any contamination instantly voids the S-rank. |
| Sample Analysis | Primary samples processed correctly. | All samples processed with perfect procedure (e.g., barcoding). |
| Final Deduction | Correctly solves the case; may mark 1-2 non-key items. | Marks all key evidence AND avoids all red herrings. |
| Unlocks | Case-specific achievements. | Progress towards the "Forensic master" achievement. |
Annotated diagram of the final case board explaining how to avoid a 'Red Herring'.
Frequently Asked Questions
Can I get a Category S on my first playthrough of a case?
It's highly unlikely. The game gives very little guidance and expects you to learn its deep systems through trial and error. A first run is best used to identify the primary evidence and learn the case's layout. Achieving an S-rank almost always requires replaying the case with foreknowledge of where the hidden items are.
What happens if I get a rank lower than B?
A 'C' or 'D' rank indicates significant evidence was missed or you reached the wrong conclusion entirely. An 'F' rank means you failed on a fundamental level, likely by finishing the case early with very little evidence or a completely incorrect deduction.
Is there a rank between B and S?
Yes. A Category A rank is possible. This typically occurs when you do almost everything perfectly but miss one minor thing, such as the hidden fiber in the tutorial, which prevents the S but is better than a standard B.
What's the point of getting all S-ranks?
Beyond personal satisfaction, achieving a Category S rank on all nine of the game's cases is required to unlock the "Forensic master" achievement.
Does the two-item carry limit affect my score?
Directly, no. The frustratingly small inventory limit is a core mechanic that forces you to be deliberate and make many trips back to your van. Indirectly, it can cause you to make mistakes out of frustration, so managing it patiently is part of the challenge of an S-rank run.
The Final Analysis
Ultimately, the difference between a Category B and Category S score is the difference between playing a detective story and performing a scientific procedure. A B-rank rewards you for solving the puzzle, but an S-rank demands you respect the process. It forces you to be patient, methodical, and observant on a level most games never ask for. While frustrating, finally earning that perfect score after a flawless run is one of the most satisfying moments FORENSIC - M.E. Protocol has to offer.