I think to have the player use two hands to do 2 tasks simultanously is a super cool base idea for a game.
it seems to me the mechanic is slightly bugged though? it seems you can always kill a fly even when the field is empty?
and maybe instead of restricting the players ability to move with cool downs, why not increase the speed in which the flies spawn?
Viewing post in Twinstick Flycatcher jam comments
One can always target a field (if not in cooldown) and then try to hit. If you can magically spawn a fly into existence by hitting an empty field, that would be a bug (and not a fly).
Maybe in a future expansion it could be you actually move the frog between fields, so there is no need for an extra cooldown if instead one can only catch a fly if on the same field.