I was surprised that the pet is out to murder people, but I appreciate that the representation of bodies being crushed is cutesy in line with the tone I expected from the art and music and the smile on the pet's face. I liked that the core mechanic of the cube being unable to stop itself once set in a certain direction matched the theme of a spiky out of control pet. I liked the addition of whistling/teamwork (and that the owner is not at all concerned about the murder). I was curious if the dirt/grass, blue, and yellow walls would react differently, but it seems to just be an artistic choice. Some of the humans seem to be naked which was a fun quirk to notice.
Great twist about how to get the right whistling angle in the last few levels.
I struggled a bit with how you have to already to holding down A or D and then press W to jump up and over. I died several times because I'm so used to AW or DW at the same time or W then A/D working.
I was tempted to quit on the second or third whistling level where you have to immediately get out of the way. Up until that point the game had just been about planning ahead, and I think I expected the game to stay at that level of low stress. Consider introducing the need for timing earlier.