Haha, the dog dressed as an alien was from The Enemy Within, not The Man Trap. I think it's just funny that they thought it was pathetic as I thought it was when I first saw it.
They did what they could and I, like many others, didn't think it was pathetic. Film f/x is all about creativity and imagination and using the tools you have at hand.
I've seen a lot of older films and TV shows were I was impressed with what they accomplished considering what little they had to work with.