1) You can buy as many as you want.
2) Instructions manual
Our will is to include the instructions manual in the physical edition as a booklet, but there are some factors to take into account. Basically 2: How many physical copies we finally sell, and the budget to make the copies and shipping. We apologize for not being able to guarantee the booklet 100% at this moment.
3) Compatible with mouse, keyboard and controller.
4) Once we officially fund NetherWorld, we'll send you a form where you'll be able to especify which physical version/s of the game you want (PC, Switch, both, etc.)