Create Zombie Survival Game Map (UNITY)

I'm looking for an experienced game map designer to create a detailed, large-scale map for my zombie survival game.

Requirements:
- Post-apocalyptic theme
- Hell-inspired terrain (like Doom)
- Key landmark: Hellish fortress
- Map should accommodate 15 upgrade/machine locations

Ideal Skills and Experience:
- Proficiency in game design software (e.g., Unity, Unreal Engine)
- Strong artistic skills for creating post-apocalyptic and hellish environments
- Experience in designing large, navigable game maps
- Attention to detail and ability to follow specific thematic guidelines

Please provide samples of previous work.