I'm not familiar with their marketing/ecosystem. Do they gather together the best games and have a whole "season" you purchase? And repeat this every year?

They got a bunch of well known developers to build a collection of games, and deliver them to Playdate devices via wifi at a pace of 2 games per week (unless you choose to skip ahead). Season one is included with the device itself, so if you even if you didn't buy or sideload any other games, you still get new games for 3 months. Season two was $39 for 12 games.

You can choose not to look up which games are included in the season and just be surprised by new games every week, and that kept the console feeling fresh. But the really brilliant part is that you got to experience the new games together with other people who got the season at the same time as you, similar to people watching the same weekly broadcast of some TV show. I find this community aspect of the experience most interesting.