Yeah ive been wrestling with some ideas on that one...Im considering using the number keys or right click to change items and using the scrollbar to change placement length - also considered just having a big green circle and letting you place it anywhere inside though if I add controller support, its become unplayable - idk...I have a few options.
Glad you liked it! Im excited to add a few more defense mechanisms such as bear traps, shields, and a legally distinguishable non-mario star(totally a mario star) haha. But im in the weird phase after a jam where you cant touch it for awhile. lol