Good first effort
I am looking at this program from the point of view of a youth/high school soccer/futsal coach. I would like to diagram both drills and plays.
* visually this program is very attractive and interactions with the drawing are smooth and work well
* the program does not support line types I need to diagram soccer plays, e.g. dashed lines. Yes, there is a feature that let's you move circle icons and leave a trail but that doesn't support multiple runs by the circle
* having the fields of all the sports on screen at launch is a negative. I want my sports only and I don't want to burn taps to find my field template or my plays.
* Support was good for templates, I mentioned futsal was played on basketball courts and the developer quickly made a new template available
* scribbling to erase the lines is interesting but you quickly find, with diagrams that have overlapping runs, that being able to modify/delete a single run is what you really need. Also, if you try to draw a zig-zag line (used for dribbling) it will be interpreted as an erase.