Any form of progression. Something that changes over time because now in the first seconds of the game you've seen everything. It could be multiple levels or indeed increasing difficulty. could be more blocks, faster blocks, bigger blocks, new mechanics. Just do what you think would be fun to play :)
The MoonBit SDK indeed doesn't have Boards and Badges yet. I've asked Applejag to look into it over the weekend, so we'll bring it in in the next release.