One of the artists behind this, Vicente Lucendo, has a case study here explaining how they made a previous project (Summer Afternoon):

https://www.awwwards.com/summer-afternoon.html

And a talk here on the same project:

https://www.youtube.com/watch?v=KSIxyyEaPr0

It's full of tips that likely informed this new project. In short, seems like:

- No game engine

- Three.js plus https://github.com/gkjohnson/three-mesh-bvh

- Houdini and Blender for modelling

- Substance for texturing

- Figma and Affinity Photo for UI

- GSAP and vanilla JS for animation

- Davinci Resolve for sound

- WebSocket/Node.js for multiplayer

Plus a lot of experience, creativity, and artistry to solve other challenges (e.g. shaders, shadows) and wire everything together into this pretty performant piece of art.

The studio also has a case study here of another project they made, with other hints about their tooling and process:

https://www.awwwards.com/igloo-inc-case-study.html

Just for anyone like me who played this and spent the whole time thinking, "this is beautiful, who are you and how did you make this?" The author names are only revealed in the credits at the end:

https://vlucendo.com/

https://x.com/michaelsungaila (nice work on the beach shader!)

https://www.kevincolombin.com/ (music)

A WebGL game where you deliver messages on a tiny planet