In chapter five of Mary Shelley's Frankenstein, all of Victor's toils are come to completion. Victor's creature lives. Prior to chapter five, readers are told about the obsessive behaviors which have led Victor to success. He has chosen the parts for his being with meticulous scrutiny. Victor has not only abandoned his family during the years it has taken him to create his being, he has also ignored his own well-being.
That said, once the creature opens his eyes, Victor is utterly horrified by it.
His limbs were in proportion, and I had selected his features as beautiful. Beautiful!—Great God!
Here, Victor's exasperation at what has come to be, even with his meticulous nature, is blatantly stated. He is utterly appalled at the fact that his creature is not the beautiful creature he desired. The use of the exclamation mark after the word "beautiful" denotes his strong feelings about how his creature was supposed to be. "Beautiful" is meant to come out angry and emotionally charged. He is angry that he spent so much time choosing the parts for his creature, which were chosen for their beauty, to only have his creature "emerge" hideous.
The second exclamation mark, "Great God!," again denotes his disgust at the physical appearance of his creature. Not only is this exclamation ironic (given God would not have created such an ugly being--God's first being was in his image, unlike Victor's), Victor's exclamation here seems almost as sacrilegious as him creating life in the first place. Essentially, God had nothing to do with the new life.