Cross-Platform 3D Open-World Game

I want to bring a fully fledged, open-world adventure to both Android and iOS, with a strong emphasis on real-time multiplayer. Think seamless exploration over a large map, team or free-for-all encounters, and shared quests rather than a linear, story-locked path. The visual target is realistic 3D—natural lighting, detailed characters, and environments that feel alive on mobile hardware.

I’m leaning toward engines such as Unity or Unreal that already handle cross-platform builds, in-app purchases, and matchmaking, but I’m open if you have an equally solid solution. Network code needs to support smooth movement sync and server-authoritative combat to keep cheaters out. I will provide narrative outlines and rough world layouts; you will transform them into a functional prototype and iterate to a polished release.

Deliverables
• Playable Android (APK) and iOS (TestFlight) builds
• Complete project source with clear folder structure and comments
• Basic backend for lobbies, matchmaking, and persistence (Node.js, Firebase, PlayFab, or similar)
• One primary biome with points of interest, NPCs, and at least two cooperative objectives
• Integrated touch UI, controller support, and performance profiling for 45–60 FPS on mid-range devices

Acceptance criteria will be a stable online session for 10 simultaneous players, no frame drops below 30 FPS on a Redmi Note 10 or equivalent, and code that compiles error-free on a fresh clone. If this excites you, tell me which engine and netcode framework you’d reach for first, and show me a clip or build of a comparable project you’ve shipped.