Yes, it is a question whether the stack includes Web assembly? Also, is there a pricing or business model for the platform/engine?

We do use some WASM yes and intend to use more in the future, but the majority of the engine is still TypeScript compiled to Javascript.

The pricing model is not yet announced, but it'll be a rev share between the creator of the game and us. More info here: https://developers.dotbigbang.com/