I felt this was just a prologue to something that could be much larger in scope and design - I was curious about the main character and why they would keep pets if they had recurring nightmares about being chased by large versions of them! You could also have the whole apartment block as one big escape scenario - with some puzzle elements and ways to barricade rooms from X-33.
Dev - If you decided to expand on this I'd keep the eerie, dread like tension throughout - you could be onto something special here...