Small studio here. We shipped a CS2 coaching tool this year, and I want to write up the engineering problem behind it, because it turned out to be the product.
The premise was that post-match demo review doesn't change how you play. By the time you sit down to watch the demo you've emotionally moved on from the round, so the lesson lands on nobody. Feedback has to arrive while the round is still happening.
But "during the round" is a brutal constraint. A call that arrives five seconds late is worse than no call at all — you're being told about a situation that's already over while a new one is in front of you. Early builds felt like being coached over a satellite delay.
Getting the whole loop under two seconds meant cutting things that had felt non-negotiable:
- Waiting for full context before speaking. It now commits on partial information, the way a human IGL does, and it is sometimes wrong because of that. Testers forgave wrong-but-timely far more readily than right-but-late. That single finding reorganised the entire design.
- Explaining itself. Reasoning got cut to roughly one clause. In freezetime you have fifteen seconds and you're buying — nobody reads.
- Continuous commentary. Constant talking got tuned out inside a single match. Silence turned out to be a feature. It now fires on discrete triggers — freezetime, after a death, positioning, peek timing — and stays quiet otherwise.
The part I didn't expect: the hard problem in coaching software isn't knowing what someone did wrong. It's knowing when they can actually hear it.
Since it's always the first question — how it reads the game: Valve's Game State Integration feed plus screen capture. No memory reads, no injection, nothing written back into the game. The same mechanism a streamer's HUD overlay uses. It doesn't surface anything the game isn't already showing you.
And the disclosure, because I'd rather say it than have it discovered: I made this. It's called Game Demon, $14.99 one-time for the base tier or $99/year for unlimited, with one full coaching cycle free and no card required. Windows 10/11 only. Still rough in places — there's a public known-issues page and a daily changelog.
Writing it up mostly because the latency lesson generalises well past CS2 — if you're building anything real-time, pick your latency ceiling first and design backwards from it.