Chris Wright has shared a wonderful tutorial on how you can recreate Spelunky level transitions in your Phaser 3 game. In the article, Chris walks you through the concept we are going to create and then he shows how we can use Scene Events and Scene Transitions to achieve this effect.
From the article: "Today we're going to take a look at how we can implement Spelunky-inspired in Phaser. You can see the finished product in the live demo and you can find the source code over on Github. We'll start by reviewing the effect and learning a bit about scene events and transitions, then jumping in to the implementation."