Mobile Game UA Video Basics: The First 3 Seconds and Vertical Format

If a mobile game ad doesn't stop the scroll, the rest of the 15 or 30 seconds doesn't matter — nobody's watching it. That's why the first three seconds are what UA (User Acquisition) video editors polish hardest. This post covers the basics teams building their first UA video tend to miss.

Why the First 3 Seconds Are Everything

On feed-based ad placements like Instagram, TikTok, and YouTube Shorts, a user's window to swipe past is barely one or two seconds. UA videos usually run 15 to 30 seconds, but the segment that actually determines completion rate is the first three. Three things need to be true in that window:

Vertical Is the Default Format

Since most UA placements live in mobile feeds, 9:16 vertical is the standard aspect ratio. Force-cropping landscape gameplay footage into a vertical frame often cuts off key UI or characters, so it's worth capturing with vertical framing in mind from the start — or, if your game is landscape, building in margin and text space within the vertical frame during editing.

PlacementCommon ratioRecommended length
Instagram / TikTok feed9:1615–30 sec
YouTube Shorts9:1615–60 sec
Interstitial (in-app ads)9:16 or 16:915–30 sec

Tips for Capturing Gameplay Footage

Keep Editing Light, Iterate Often

A UA video isn't something you make once and move on from — it's closer to a disposable asset you produce in multiple versions (different opening 3 seconds, different captions) and compare against performance data. Cutting gameplay footage into vertical format and quickly producing several versions with different captions and openers is the core of the work.

Speed of iteration matters more than polish in UA video production. Four rough cuts that only differ in their opening three seconds will usually teach you more about what works than one beautifully finished video.

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