Love the idea, monster creation in a Dungeon Keeper-style game? Whats not to love? Still, what you have is a great base of a game, but it lacks all the important stuff around it. I think that's rather obvious to what so lets look at what you have so far.
I enjoyed the variation that I was given, but felt needlessly hindered in my creation of monster by forcing me to have at-least 1 eye, body and leg. If I HAVE to have those 3 no mater what, why not already have them placed on the mold? Also, was there any difference where I placed the body parts? If not, It should, otherwise the 3x3 grid has no point other then for the visual-flair.
It was also rather annoying that the monsters went strait up after killing the visible knights on the field, it would have been better to have them go back to the center and only react as soon as a knight is at least visible. Connected to this issue is the effects of the body parts, its interesting that every parts have a purpose and gives a bonus if you have more, however because of the limited build space it felt pointless to have more then 1 leg and 1 eye. In the end after killing a visible knight, the monsters just clogged the entrance anyway and stopped moving, so exchanging legs for more life of damage was always better. Also, having more legs actually made the shooting part worse as the monster stopped shooting when in melee.
Hope to se a more full fledged game in the future! So for the most Original I have played in the Jam.