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Automating Marketing Assets with Midjourney, After Effects, and Runway

Indie teams rarely have a dedicated marketing artist. You need key art, trailers, and social clips on a tight budget and schedule. A practical way to get there is to combine AI image generation (Midjourney), motion and compositing (After Effects), and AI video (Runway) into a repeatable pipeline. This guide walks you through that pipeline so you can automate more of your game marketing assets without sacrificing quality.

Why Automate Game Marketing Assets?

Marketing eats time that could go into the game. Manual key art, trailer edits, and social clips scale poorly when you are a small team. Automating parts of the workflow gives you:

  • Faster iteration – Try more concepts and variants without waiting on a single artist.
  • Consistent look – Reuse style prompts and templates so store pages and social feel cohesive.
  • Lower cost – Fewer outsourced assets while you keep control of the final look.
  • More formats – One concept can feed Steam capsules, Twitter cards, and short video clips.

Midjourney covers concept art and static key art; After Effects handles motion, text, and compositing; Runway adds AI-generated video (e.g. simple cinematics or B-roll). Used together, they form a pipeline you can run yourself or with one generalist.

Step 1 – Key Art and Concepts with Midjourney

Start with a clear brief and a small set of style-defining prompts so everything downstream stays on-brand.

Define the look once

Write 2–3 Midjourney prompts that define your game’s mood, palette, and style. Include:

  • Art style (e.g. painterly, low-poly, pixel art).
  • Lighting and time of day.
  • One or two reference games or artists (e.g. “in the style of Hollow Knight”).
  • Key elements (character, prop, environment).

Example for a cozy farming game:

Cozy isometric farm scene, soft lighting, warm palette, in the style of Stardew Valley key art, character in overalls, --ar 16:9 --v 6

Generate variations, then lock the best

  • Generate 20–30 images per concept.
  • Pick the 3–5 strongest and upscale them in Midjourney.
  • Export at highest resolution you need (e.g. 2x or 4x) for Steam capsules and social.
  • Save the exact prompts and settings so you can regenerate in the same style later.

Use Midjourney for more than one key frame

  • Hero key art (e.g. 16:9 for trailer open).
  • Character or prop close-ups for social posts.
  • Backgrounds or mood plates for After Effects composites.
  • Optional: multiple angles of the same scene for simple “animation” in the edit (crossfades, pans).

Pro tip: Add --style raw or specific --stylize values once you like a look, and document them in a small “brand” doc so future prompts stay consistent.

Step 2 – Motion and Compositing in After Effects

After Effects is where static art becomes motion. You do not need heavy 3D; simple moves and text carry most indie trailers.

Import and prep Midjourney art

  • Import your chosen key art and variants as compositions or layers.
  • Use consistent resolution (e.g. 1920x1080) so you can reuse the same project for trailer and social.
  • Cut or mask to the most important area so letterboxing or reframing does not feel accidental.

Add simple motion

  • Ken Burns – Scale and pan on a still (e.g. 5–10% scale over 3–5 seconds). Ease in/out so it feels intentional.
  • Parallax – Separate foreground and background in Photoshop (or use Midjourney layers if you have them), then animate at different speeds in AE for depth.
  • Reveals – Wipes, fades, or light leaks to transition between key art and gameplay.
  • Text and UI – Animate title, tagline, and CTA with simple position/opacity keyframes. Keep fonts and colors consistent with your store page.

Use templates to save time

  • Build one “trailer open” template: key art + logo + tagline + music hit.
  • Duplicate and swap the key art and text for each game or update.
  • Use a second template for short social clips (e.g. 9:16 or 1:1) so you only replace the hero image and caption.

Rough timing

  • 0–3 s: Hook (best key art or a strong gameplay moment).
  • 3–15 s: Core loop or features (gameplay + short text or voice).
  • 15–30 s: Call to action (title, platform, release window).
  • Keep a 30–60 s cut for Steam; a 15–30 s cut for Twitter/YouTube Shorts.

Pro tip: If you use Adobe Media Encoder, set up a preset for “Steam trailer” and “Social square” so export is one click after you finish the edit.

Step 3 – AI Video with Runway (Optional but Powerful)

Runway can generate short video clips from images or text. Use it for B-roll, simple cinematics, or “living” key art so your trailer feels less static.

When to use Runway

  • Short clips (e.g. 4–10 s) of atmosphere: clouds, water, leaves, smoke.
  • Simple character or camera motion from a Midjourney still (e.g. “camera slowly pushes in”).
  • Extra variety when you do not have in-engine cinematics.

Basic workflow

  1. Export your best Midjourney frame as a high-res image.
  2. In Runway, use “Image to Video” and describe the motion you want (e.g. “slow zoom in, subtle wind in the grass”).
  3. Generate a few takes; pick the smoothest and most on-style.
  4. Export and drop into After Effects as a layer. Add a subtle blend (e.g. overlay or soft light) if the AI clip feels flat compared to your grade.
  5. Use these clips as B-roll between gameplay or under text.

Keeping style consistent

  • Feed Runway the same style of image you use in the rest of the trailer.
  • Keep prompts simple and motion subtle; aggressive motion often looks less polished.
  • If a clip feels off, try again with a different prompt or use it very short (1–2 s) so it reads as atmosphere rather than focus.

Pro tip: Runway credits are limited on free tiers. Use them for a few hero shots (e.g. trailer open and one or two B-roll cuts) rather than the whole timeline.

Step 4 – Tie the Pipeline Together

Folder and naming

  • One folder per game or campaign: KeyArt, Exports, AE Project, Runway Clips.
  • Name files by use: hero_16x9_v2.png, trailer_steam_30s.mp4, social_9x16_15s.mp4. You will reuse these names in store pages and social.

Checklist before you ship

  • [ ] Key art matches store capsule and social thumbnails (same crop or very close).
  • [ ] Text (title, tagline, CTA) is readable at small size and on mobile.
  • [ ] Music and pacing match the tone of the game (and you have rights to the music).
  • [ ] One short (15–30 s) and one long (30–60 s) cut so you can A/B test or use per platform.

Reuse for ongoing marketing

  • New content update: swap key art and one or two Runway clips, keep the same AE structure.
  • Social: pull a single strong frame from the trailer or key art and add a short caption template.
  • Events and festivals: same pipeline, new prompt set for “festival” mood (e.g. brighter, more dynamic).

Common Pitfalls and Fixes

Midjourney looks generic

  • Narrow the prompt (specific art style, palette, and one clear subject). Use --style raw or lower stylize to reduce “AI sludge.”
  • Generate more options and only use the few that feel on-brand.

After Effects feels flat

  • Add a very subtle vignette, grain, or color grade so the composite feels intentional. One adjustment layer can do this for the whole sequence.
  • Vary scale and position; avoid static holds longer than 2–3 seconds unless it’s a deliberate pause.

Runway clip doesn’t match

  • Use the same key art as the rest of the trailer as the Runway input. Describe motion only; avoid asking for new content in the same clip.
  • Keep clips short and blend them with crossfades so small style shifts are less noticeable.

Pipeline takes too long

  • Build and save AE templates after the first trailer. Next time you only replace assets and tweak text.
  • Limit Runway to 2–3 clips per trailer. Use Midjourney + AE for the rest.

Summary

You can automate a large part of game marketing asset creation by:

  1. Locking a look in Midjourney with 2–3 reusable prompts and using them for key art and concept frames.
  2. Adding motion and text in After Effects with simple moves, one or two templates, and consistent resolution.
  3. Adding optional AI video in Runway for a few B-roll or “living” key art clips.
  4. Reusing the pipeline for every game or update so the second and third trailers take a fraction of the time.

Start with one trailer and one social format. Once the pipeline is in place, you can scale to more formats and platforms without scaling the team. For more on shipping and marketing indie games, see our guides on game marketing and help articles on store pages and trailers.

Bookmark this post and revisit it when you plan your next trailer or campaign. If you found it useful, share it with other indie devs who are building their marketing pipeline.