Game available here https://store.steampowered.com/app/1882300/Elegos/
One of the core pillars we agreed on was for gameplay that is as unobtrusive as possible and to let the player into the game as quickly as possible. So, we made Phacos feel like a playground.
Let's take one of the first areas encouraging you to explore verticality.
To ease up the workload on the team I also used View Gates - key locations on the map where there was clear design guidelines of what the player should or should not be able to see.
By embracing this method, it allowed the team to function much more independently. When everyone was clear on what the end goal is, things run a lot smoother and for the different disciplines to collaborate.
In terms of invisible tutorials it took some guts to let the players navigate rather than railroad them. For example, with verticality there is no way but up. But! If they miss secondary areas to explore they can still see them from the staircase that leads them to the landmark.