yes, I think that the –en ending is usually the noun for the activity (so in English we’d probably use the gerund), while the –ung ending tends to be the noun describing the result of the activity.
Das Kochen = cooking (Das Kochen macht spaß)
Das Spielen = gambling or playing.
Die Entscheidung = decision.
Die Leistung = perfomance.
But I suspect there are lots
of exceptions (there usually are!
Hope that helps.