Current ads are 4 seconds, reaching level 30 in about 1 hour (unsure if ads will become 1 minute+ later)

Currently, ad rewards give 250 diamonds, and each ad takes about 6 seconds. Watching four ads allows you to spend 900 diamonds on a magic wand sequence, granting a lot of combo experience. Leveling up sometimes triggers double experience. It's best to save up over 4000 diamonds and then continuously spend diamonds to arrange sequences and earn experience when double experience is active. Don't watch ads for diamonds during double experience; they only last 60 seconds. You can reach level 30 in about an hour. Using a gem increase item for an hour maximizes efficiency. I'm too lazy to complete the hidden quests for levels 60, 100, and 200 later.