Short answer / recommendation
If you need stronger style-transfer and much better compositing than Midjourney for stylized 2D game concepts, use a two-track workflow: a web-friendly, artist-focused service for rapid concepts (Leonardo.ai / Runway) and a local Stable Diffusion stack (AUTOMATIC1111 or ComfyUI + ControlNet + LoRA) for pixel-level compositing and repeatable style transfer. Use ChatGPT to iterate and formalize prompts and batch instructions.

Why this combo
- Leonardo.ai / Runway: quick, polished concept passes, good UI, fast experimentation and style packs. Great when you want many directions fast and a pleasant web UI for non-technical artists.
- Local Stable Diffusion (AUTOMATIC1111/ComfyUI): full control — img2img for style transfer, inpainting/masking for compositing, ControlNet for pose/layout guidance, LoRAs for consistent artist style, and local hardware for speed/privacy and predictable outputs.

Decision criteria (pick what's most important)
- Control & compositing granularity: choose local Stable Diffusion + ComfyUI/AUTOMATIC1111.
- Speed of iteration & team accessibility: pick web tools like Leonardo.ai or Runway.
- Privacy & asset ownership: local pipeline wins.
- Budget & hardware: web tools if no GPU; local if you have an NVIDIA GPU or cloud VM budget.
- Team size & workflow: centralized web tools for larger non-technical teams; local for small art teams that want deterministic reproducibility.

Best-for / Avoid-if
- Best-for: artists needing layered edits, masked inpainting, style transfer with consistent character/asset look, and asset-level versioning.
- Avoid-if: you lack a GPU and cannot afford cloud compute (then use web services), or you need purely painterly outputs without strict compositing (Midjourney or Leonardo.ai alone may suffice).

Practical checklist (step-by-step)
1) Gather references: 6–12 style frames, palette, breakdowns (silhouettes, closeups).
2) Base pass: generate rough compositions on Leonardo.ai or Runway to explore silhouettes and colors.
3) Export anchor images and masks.
4) Local refinement: load into AUTOMATIC1111 or ComfyUI; use img2img for style transfer (high denoising for heavy stylization, low for texture retention).
5) Use ControlNet (openpose/hed/seg) to lock pose/layout while changing style.
6) Inpaint/mask to composite assets (weapons, UI elements, lighting), iterating passes rather than huge changes.
7) Apply LoRA or fine-tuned checkpoint to lock a consistent game style across assets.
8) Upscale with Real-ESRGAN or native upscalers and finish composites in Photoshop (layers, color-correct).
9) Version and name files clearly (concept_v01_base, concept_v01_masked_inpaint).

Quick tips
- Use small LoRA models for consistent style instead of changing checkpoints constantly.
- Keep a library of masks and control maps (pose/segmentation) to speed future composites.
- Use ChatGPT to draft structured prompts and batch-generation instructions for teammates.

If you want, I can suggest exact prompt templates, a minimal AUTOMATIC1111 settings list, or a Runway/Leonardo quick-start checklist tailored to your budget and team size.

Compare ChatGPT and Gemini