Board Thread:General Discussion v2.0/@comment-26347196-20151109173852/@comment-25398349-20180130133243

Yeah, doing Flowey a lot would make you a lot easier at fighting him. Sans definitely doesn’t have checkpoints. Because he's completely reset (so to speak) after a death, but the SOULs remember you saved them, so new ones just keep helping. Though that last part is just dumb luck. You just have to survive Flowey long enough. Unless there’s a hidden mechanic summoning them faster.