Thanks so much for the detailed feedback! We had a lot of ground we wanted to cover and ended up having to cut a lot due to time constraints, as it typically goes in the jam!
On the topic of keyboard presses, we actually wanted 3 units total, with the addition of a wizard/archer. A stretch goal was to have the 3rd unit unlockable and would've been summoned on the E key. But after the jam, while sending this to our friends, we realized man this game would've lent itself to mobile pretty easily. We wanted to have a HUD anyway with icons of each unit, and it would have been very easy for us to have two methods of input. 1) The QWE keys dropping on mouse placement, and then 2) Selecting a unit via the HUD, and left clicking/tapping on the screen to drop the unit.
Our other stretch goal, was having items spawn that would've grabbed the vampire's attention, such as powerups, shields, and health potions, but the would still always prioritize the knight. That would've created gameplay where if you didn't have a knight, distracting the vampire and guiding him away from those things (and hopefully not toward!) you'd be in trouble.
There's a little bit of insider info for you :) once again thanks for the feedback and we enjoyed your game as well!