Too Long; Didn't Read
There are 907 (more than 74%) of packages which name flutter in particular. Flame is Flutter's top game engine as for September 2019. Flame's simplicity is great in a way that allows you to simply read its sources and quickly modify your code to do what it's supposed to do. Flutter gives you full control over what's displayed on the screen, but there's not much Dart code left which uses common Flutter APIs, or Widgets. Some limitations: Canvas contents could only be accessed asynchronously and only in order to be accessed via PictureRecorder.