Here is a question-by-question breakdown:

Innovation and the Economy

Obama: I will throw money at research and set a goal of 100k STEM teachers.

Romney: I will fix immigration, privatize government training programs, lower corporate taxes, reduce regulation, protect IP, free trade, offer k-12 educational "choice", and politically polarize government research spending. Also, Obama politically polarized his research spending, so he sucks.

Climate Change

Obama: I agree that climate change is an issue, and I have proposed (and will continue to propose) carbon pollution limits, reduced emissions, and reduced dependency on oil.

Romney: Waffle, waffle: warming is occurring, and it's partly man-made, but there's no "scientific consensus". Science doesn't dictate policy. Obama sucks, it's called "global warming", not "america warming", so it's China's fault. Cap and trade sucks, carbon tax sucks, let's do a "no regrets policy" that will reduce emissions but not harm the economy. That means "clean coal" and "safe nuclear", not hydro or solar power.

Research and the Future

Obama: I spent 90 billion on research into clean energy. I will also continue investing in medical and security research. Also, permanent R&D tax credit.

Romney: Obama spent 90 billion dollars on a failed attempt to promote green energy. I would have spread that out over 20 years. I will give money to corporations for research rather than give the money to scientists. Also, Obama sucks.

Pandemics and Biosecurity

Obama: We need to work internationally to help address communicable diseases.

Romney: We need to invest in public health monitoring systems. Also, Obama stifles medical innovation. Did I mention he sucks?

Education

Obama: We need to focus on STEM, goal is 100k STEM teachers, announcing federal program: STEM Master Teacher Corps.

Romney: Education sucks, A Nation at Risk, only American politics is suckier than education. Spending on education sucks. Teacher unions suck. Strangely, Obama doesn't appear to suck. I will privatize education with charter schools, transfer public school funding to said private schools (I call this "enabling choice"), penalize teachers whose students don't test well, and try to hire "better" teachers.

Energy

Obama: "All of the above", increase fuel efficiency standards, reduce dependence on foreign oil. Renewable energy.

Romney: Increase "domestic energy production" (he probably means oil), Obama and green energy sucks, where's my Keystone XL Pipeline? Drill, baby, drill.

Food

Obama: Give the FDA the resources, authority, and tools to do their job. Strengthen standards, support certified organic initiatives.

Romney: Preventative practices are best set by the people who produce the food, not government. Only they know whether or not a particular requirement will be profitable -- I mean feasible. I will have the FDA partner with growers and producers to determine the correct standards to use. Obama.... doesn't suck this time?

Fresh Water

Obama: I support water conservation and waste water programs through grants, and will work collaboratively with communities to ensure they have access to fresh water.

Romney: Lawsuits against businesses for clean water suck. Unnecessary constraints on business suck. I support market-based incentives to improve the water in our nations lakes and rivers.

NOTE: Neither candidate addressed the issue of pollution.

The Internet

Obama: Free internet is important, but so is IP. Draconian anti-piracy policies must not reduce freedom of expression or undermine the internet. Also, we need cyber-security.

Romney: The government shouldn't manage the Internet. It's owned by private companies, let them manage it. Obama sucks and is trying to take over the Internet. Net Neutrality sucks, broadband providers should be free to prioritize their traffic -- after all, they own the Internet. The UN sucks and wants to take over the Internet.

Ocean Health

Obama: We are investing in restoration projects, and will continue to do so. We will also support conservation efforts.

Romney: The economy is based on fishing. We need less regulation of fishing, and I will protect the health of fisheries, because the economy is based on fishing.
NOTE: Once again, neither candidate addressed the issue of pollution.

Science in Public Policy

Obama: I support transparency and public participation, and I base my policies on the best science available without distortion or manipulation. I will continue this in my next administration. I do not support distorting science to fit a political agenda, and make decisions based on facts, not ideology.

Romney: I will base my policies on the best available scientific and technical information, and will avoid manipulating science for political gain. Obama sucks and distorts science to fit his agenda. He will get rid of mercury pollution by bankrupting the coal industry. Also mercury pollution is measured in dollars. Finally, I will establish a "regulatory cap", forcing agencies to spend as much time repealing and streamlining outdated regulations as they do imposing new ones.

Space

Obama: We will continue to focus on sending humans to an asteroid by 2025 and Mars by 2030. Space is exciting and inspirational work.
Romney: Space is crucial to spurring the economy, innovation, and national security. Also, it shows how awesome we are to other countries. I will not give NASA more money, I will clarify their priorities: practical missions, security/defense/military use, and stuff that can be used by corporations for profit.

Critical National Resources

Obama: China sucks for not exporting more rare earth minerals, and we're suing them for it. We need to be less reliant on other countries (like sucky China), so I'm going to focus on research for electronics that don't rely on rare earths.

Romney: The US used to produce rare earths self-sufficiently. But regulation sucks, and that's why we don't do that anymore. Oil is a similar problem, and I'm going to spend two paragraphs on how we need to drill, baby, drill. Apparently rare earths are energy.

Vaccination and public health

Obama: Obamacare will help make vaccinations affordable and available.

Romney: We need to make vaccines, which means we need to strengthen the economy so medical companies can profit from vaccines, giving them incentive to make new ones.