what engine is deltarune chapter 5 and 6

Deltarune Chapter 5 and 6 are reported to be made with GameMaker. Recent coverage around Chapter 5’s release also describes Toby Fox’s updates and development progress for Chapters 5 and 6, but does not indicate a different engine.

What that means

• GameMaker is the engine associated with Deltarune’s development, including the later chapters.
• The current public reporting around Chapters 5 and 6 focuses more on release timing and progress than on any engine change.

Quick note

If you meant a specific platform version or a modded build, that could change the tooling around the game, but the base answer is still GameMaker.