Retro Mobile Multiplayer Racing Game

I’m looking to have a straightforward but addictive car-racing game built for mobile devices. The core of the experience should feel like the arcade classics—bright pixel art, 2-D/2.5-D camera angles, chiptune sound, and that unmistakable retro vibe—yet it must run smoothly on today’s iOS and Android phones.

Gameplay
• Online multiplayer is essential. Players need to jump into quick city-street races with friends or matchmade rivals in seconds.
• Tracks are all urban: tight corners, traffic-light drifts, alleyway shortcuts—the city itself is the course.
• Cars and environments can stay stylised rather than photorealistic; lean into colourful sprites and exaggerated effects.

Core features I expect at first launch
- A lobby system for creating or joining races (4–8 players).
- At least three distinct city circuits, each with day and night variants.
- Simple touch controls (tilt optional) and on-screen UI that is intuitive across screen sizes.
- Basic progression: unlockable cars or palettes earned by racing, no heavy RPG layer for now.
- Leaderboards and a quick-chat or emoji system so races feel social.

Tech & delivery
Unity or another cross-platform engine is fine as long as you can give me a single codebase and builds for both major mobile stores. I’ll need source code, art assets, and a brief document explaining how to add new tracks or cars later.

Acceptance criteria
1. Both Android and iOS test builds install and run without crashes on mid-range devices from the past three years.
2. Two players on separate networks can complete a full race with sync that feels smooth (≤150 ms latency).
3. Visuals match the stated retro aesthetic and all UI elements display correctly on common aspect ratios.

If this scope is clear and the genre excites you, tell me how you’d tackle networking, what retro art pipeline you prefer, and an estimated timeline for a first playable.