Spider-Hero City Game Prototype

I want to build a small but fully playable vertical slice of an action-adventure inspired by “Hero x Hero.” From the first launch, players must be able to:

• Control a Spider-Man–style hero who can run, jump, climb, and swing through an explorable city.
• Enter a secure plaza that acts as both the social hub and the place where soul blocks are opened. Inside that space players can freely trade characters, weapons, items, currency, and the soul blocks themselves.
• Venture into surrounding horror zones where enemies roam and missions trigger. These areas supply challenge, narrative hooks, and a clear contrast to the safety of the plaza.

Soul blocks are a core loop item. Players should earn them three ways: as drops for defeating enemies or completing missions, as hidden finds while exploring any district, and by purchasing them with in-game currency at a shop terminal in the plaza.

I’m open on engine choice, but please stick to mainstream tech (Unity, Unreal, Godot) so future content additions remain straightforward. What I need from you is a runnable build plus clean, well-commented project files. If you leverage third-party assets or plugins, list them clearly and keep licensing simple for commercial release.

Show me past real-time action or open-world work and outline how long you’d need to deliver this prototype.