I was curious, so I decided to try this out last night btw. You're right. Took a bit longer than 5 minutes...maybe 10. Made a few adjustments-regular pull ups instead of holding, held the pushup in 'down' position for 3 seconds each, to make 100% certain I wasn't cheating, and side blade kicks instead of snap kicks..don't like snap kicks.
I'm also not in the greatest shape at the moment. It's a good starting point, but if you're still new to working out, I would make sure to add more cardio, add something for your core, and way more stretching. I hate stretching, I think it's the devils work, but it's still important.
Well, I don't know exactly how long it takes, I don't check out the clock all day, 30-45 minutes was how long I felt it takes, but maybe I unconsciously took into consideration the time needed to go to the park to do that workout and back.
For my core, I do leg raises. What's wrong with them?
About stretching, there are different views, even among experts, about its usefulness. I guess it depends on the individual's body. My experience taught me that my only muscles I need to stretch (because I pull otherwise) are my inner thighs.