Oh, also, I think there's a visual glitch when you send a worker that's mining to go chop a tree. The villager will continue the mining animation until they get to the tree. Not that important, but I thought you should know.
Thanks for the feedback! To read that you have spent hours playing our humble demo is very encouraging.
To answer your complaints:
1. I've added screen sensitivity as a setting to our to do list.
2. We primarily tested the game on friends who have played many RTS games for years, before uploading the first build, so please don't let this demotivate you. You're not the first one complaining that easy is not really easy. We want the game to be accessible to new players and will tweak the difficulty levels. Also, a unit that can heal units is on the road map!
Thanks for the bug report, will look into it!