Did you notice that Dreamland has some scenes with zoom effects, others with parallax, and even some with animated parts, like Summer’s legs at the beginning of the game? To achieve this, the developer created multiple layers for each scene and used programming to animate and move them. This puts a heavy load on the Ren'Py engine, both in terms of processing and memory usage. The game you mentioned, on the other hand, uses only static images and frame-by-frame animations, which is much lighter and generally more suitable for projects made with Ren'Py.