In a retrospective article detailing the making of Chapter 5, developer Toby Fox explained that the chapter's platforming mechanics were conceived shortly after Chapter 2's release in 2021, and were developed as a prototype before expanding in scope late into Chapter 4's development. According to Fox, a major issue with the mechanic's development was allowing it to mesh properly with the standard RPG gameplay of Deltarune, resulting in the formation of the ACT system and the addition of dialogue and RPG-style encounters in these sequences. The ACTs themselves originally encompassed a broad range of ideas before being whittled down to using Susie's Rude Buster and Ralsei's hanging ability. Fox also stated that the developers had to consider the possibility of Deltarune being many players' first experience with platforming gameplay, especially since Chapter 5, a relatively late point in the story, would be the first time it would appear in the game. Consequently, the level design was simplified to keep the "actual jumping challenges" from becoming too intense barring a few optional areas.