Pixel art is fine. I'm not sure who started the rumor that it wasn't, but it wasn't a map judge.
Parkour should not be criticized on the basis of "it's pixel art". Maps that meet server needs will be accepted whether or not a particular player likes them or not. That is up to server staff like
@Emmalouise to decide based on far more criteria than whether or not it is pixel art.
Keep that in mind when reading players opinions. Many give great advice that has helped map makers learn and improve... others just seem to criticize for the sake of being critical.