You're a crafty one, Barry Allen!
I just love this issue! Whoever wrote this had a wonderful sense of humor and it shows.
The Writing
This issue is very good. Personally, I like this second appearance of Mirror Master (Sam Scudder) more than I liked his first appearance. This story seems to flow more easily, which shows that the writer, John Broome, is getting comfortable with Barry Allen and his rogues. The second story is actually good. Normally stories like "Secret of the Sunken Satellite" that don't have characters who appear again (other than in reprints) are iffy. However, this story is entertaining and had a sweet message at the end, which I liked.
Cameo
In the previous issues of Flash (and Showcase), we have not had a mention of the rest of the DC universe. I mean, we did see Jay Garrick in a comic cameo in the first issue, but that was really a Flash- related cameo. However, there is not a mention of Wonder Woman, Batman, or any of the other major heroes at the time published by National Comics (note: their name was not changed to DC offically until 1977 though you will see DC on the cover). No character or team outside of the Flash family has appeared; until this issue that is.
I mean sure, it is not a character or anything like that, but the mention of the Daily Planet is interesting. I'm not sure if the paper on the right is supposed to be the Daily Star, but that too is a nice cameo if intended.
Story within the story
Within "return of the Mirror Master", we get to see more of the ups and downs of Iris and Barry's relationship. I always love stories like this because it shows how much a couple can grow before it prospers and this story is no different.
This will mark the first break of their relationship (that we see). I suspect I will see more breakups and stuff in this relationship . I am sure many users might know more than me about their relationship and you will say something about it, but it is interesting to see it play out from the beginning.
Conclusion
This issue is wonderful. I really want to talk about what Barry did, but I won't because that would spoil everything. i will say I might consider Barry Allen a villain just by that one action, though I wouldn't blame him...