I played it this afternoon. It was good. I feel like the game is being built to maximize the marker, so if anyone is worried this is a platformer with a gimmick slapped on shouldn't.
The demo concentrated on drawing vines, cutting them for swinging and creating branches to extend ledges. Each challenge involving these elements was explicitly crafted to use these mechanics and, while holding the trigger to activate the marker is different, it added something fresh to a game that would be sorely lacking without.
The actual platforming and controls were tight with a decent jump arc and natural speed. I'd say keep an eye on it, it was pretty good.