Awesome gamedev youtuber/streamer Vimlark tried out Boatyard Boss on stream today: 
https://www.twitch.tv/vimlark/v/1554250347?sr=a&t=7478s

The biggest gripe was the issue with line drawing when the mouse left the game window. This is fixed in tonight's HTML build (HTML21)!

The second largest point of feedback was that collisions are not noticeable enough. Adding sounds and visuals for collisions and near-collisions has always been on the todo list, but it's been moved to the top, standby!