In the original game, you have to play through the entire fight sequentially. A great simulator lets you select specific phases—such as practicing just the green soul's frying pan attack—so you can master the patterns.
: Fan projects like those in Undertale Yellow have even been compared to the original, with some fans preferring the "uncanny" and "creepy" art style shifts in fan-made phases over the classic Photoshop look. Popular Omega Flowey Simulators omega flowey fight simulator better
