My pleasure, very cool start and I hope you keep improving and expanding it after the jam!
As for the bug, it was probably one of those freakishly rare glitches. I was in the 2nd room with the drop-down gates and had fought about 7 of the instantiated creatures. I remember using the needle attack upwards soon before the error occurred. Is there any way an attack could disrupt the instantiation point? —This is my best guess as the first room worked fine