Okay kiddo, so let me explain the criticism of pandeism in a way that you can understand.
First of all, pandeism is a belief that combines two ideas - pantheism and deism. Pantheism is the belief that everything in the universe is divine and connected to each other. Deism is the belief that God created the universe but doesn't interfere in it. So, pandeism says that God created the universe and then became one with it, which means that God is everything and everyone in the universe.
Now, some people criticize pandeism because they believe it doesn't make sense. They think that if God created the universe, why would God then become one with it? It seems kind of pointless.
Another criticism of pandeism is that it doesn't explain anything. Sure, it might sound nice to say that God is everything, but what does that really mean? How does that help us understand the universe or answer any questions we might have about it?
So, in summary, some people criticize pandeism because they don't think it makes sense or explains anything about the universe.