How to Analyze SC2 Replays

You just lost a game and you’re pretty sure it was because of that last fight near their fourth base. Maybe it was. Or maybe you were already behind five minutes earlier and didn’t realize it. The only way to know is to watch the replay, and most players skip this step because they don’t know what to look for.

Why Reviewing Replays Actually Works

There’s a gap between what you think happened in a game and what actually happened. In the moment, you felt like you were macroing well and then got overwhelmed by some unfair composition. In the replay, you’ll see you stopped making workers at 44 supply, floated 1200 minerals for two straight minutes, and attacked into a concave with siege tanks already set up. That gap is where improvement lives.

A Diamond Zerg player I know was stuck for an entire season. He thought his problem was late-game army control. After reviewing ten of his losses, the pattern was obvious: he was hitting 66 drones in every single game regardless of what his opponent was doing. Against two-base all-ins, against greedy thirds, against everything. His economy wasn’t the issue. His scouting was.

Start With the Income Graph

Open the replay and look at your income tab first. This is the most honest part of the replay because it doesn’t lie. Either you were making workers or you weren’t. Look for flat spots in your mineral income line. Every flat spot is a period where you stopped producing workers or lost them and didn’t replace them fast enough.

Then check if your unspent resources stayed low. A rising income line with rising unspent minerals means you’re mining plenty but not spending it. That’s a production issue, not an economy issue. You need more production facilities or you need to be hitting your production cycles more consistently. Compare your income curve to your opponent’s. If their line pulls ahead of yours around the 5-minute mark, that tells you exactly when things started going sideways. For a deeper look at what your economy numbers should look like, check the economy guide.

Army Composition Over Time

The army composition tab is where you figure out if you got hard-countered or if you just had less stuff. There’s a real difference between losing because your opponent made 15 Immortals into your Roach/Ravager and losing because you only had 30 supply of army when they pushed with 70.

Pay attention to when your opponent switches tech. If they were making Marines and Marauders and then you see Liberators and Ghosts show up at the 9-minute mark, that transition is worth noting. Did you scout it? Did you react? A lot of mid-Diamond games are decided by one player adapting their composition and the other player just making more of whatever they started with.

Battle Analysis: Fights You Shouldn’t Have Taken

Not every engagement is worth taking. In the replay, look at each major battle and ask yourself: did I walk into this fight or did I choose it? Running your bio army up a ramp into Colossi is a positioning mistake, not a composition mistake. Engaging Lurkers on creep without detection is just giving away units.

The most useful thing battle analysis reveals is trades. You might win a fight and lose 2000 resources of units while only killing 800 resources of theirs. That feels like a win in the moment because you hold the ground, but you just lost the game in resources. Look at the numbers, not who retreated. Some fights you should have walked away from entirely. If your army is worth less than theirs and they’re sitting in a defensive position, taking that fight is how you throw a lead.

Build Order Comparison

Pull up both players’ build orders side by side. You want to figure out whether you were behind from the opening or if the game went wrong later. If your opponent’s natural expansion finishes 30 seconds before yours, that compounds. By the 7-minute mark, those 30 seconds translate into a worker lead, which translates into a production lead, which translates into an army lead.

Compare your supply timings too. If you hit 100 supply at 8:30 and your opponent hit it at 7:45, that 45-second gap is worth investigating. Was it a supply block? A late expansion? A floating 600 minerals while your barracks sat idle? The build order comparison tells you where the gap opened; the rest of the replay tells you why.

Common Mistakes You’ll Find

After reviewing a few of your losses, patterns emerge. The most common ones, roughly in order of how much they cost you:

• Gaps in worker production. Even a 15-second gap in Probe production at the 3-minute mark costs you hundreds of minerals over the course of the game. Check your worker count at 5:00 and compare it to where it should be for your race and build.
• Supply blocks. Easy to miss while playing, obvious in replay. Every supply block is effectively a pause button on your entire production. Two 10-second blocks in the first six minutes can put you a full cycle behind.
• Late expansions. If you’re on one base and your opponent is on two, you need to be doing damage right now or you’re falling behind every second. A lot of Platinum players take their natural 30 to 45 seconds late and never make up the difference.
• Banking resources. Having 2000 minerals in the bank means you could have had 15 more Marines on the field. That’s an entire medivac load. If you’re consistently floating above 500, you either need more production buildings or you need to spend before you move out.
• Forgetting upgrades. +1 attack finishing 20 seconds before a major fight can flip the outcome. If your replay shows you started +1 a full minute after your opponent, that’s a build order problem, not a micro problem.

How Automated Analysis Helps

The problem with reviewing your own replays is that you’re biased. You remember the fight you lost and forget the two minutes of idle production before it. You fixate on the opponent’s “broken” unit instead of noticing you had zero detection. An AI reading the same replay doesn’t have those blind spots. It sees the raw numbers: your worker count at each minute mark, every gap in production, every resource float, every fight where you traded down.

Automated analysis also catches things that are tedious to check manually. It can compare your build order timings against known benchmarks and tell you exactly where you deviated. It can score each battle by resources lost versus resources killed. It can flag the exact moment your economy fell behind your opponent’s. You could do all of this yourself, but it would take twenty minutes per replay instead of a few seconds.