OK, I'm going to play devil's advocate here to make you examine your decision and hopefully not have regrets further down the line - I wish you the best in whatever course you decide to pursue!
I've lived for multiple years in both Dundee and Manchester and I agree that Manchester has a nicer city centre - if you were considering Edinburgh instead then I would say it's worth braving the cold for!
CS is a wide field, sure, but so too is games programming and you probably won't find all of it interesting. If you find work at a large games studio then you could easily end up working on or specialising in areas such as analytics, automated QA, databases, dev ops, GUI development, network programming, tools development, or some other less glamorous part of games development. If you find yourself work at a small games studio then you will likely have to wear many hats, not all of which will suit you. It seems like the MMU course has CS modules in it such as "Databases" and "Data Structures and Algorithms" - will you be able to stand these? And to focus on the 1st year, it doesn't seem like there are many modules with a games focus as "Programming", "Maths for Computing" and "Graduate Skills" all seem quite general. My main concern with the curriculum is that it tries to cover both games design and games programming, which are two very different fields. The design modules will come at the expense of further technical modules and the course looks to have quite a few less technical modules than Abertay.
Have you researched the games industry and read the blogs of people who are in it? It's a career that you should embark on for the passion because the pay is towards the low end of the scale for programming jobs, there is often unpaid overtime ("crunch"), and job security is low (one badly-reviewed game can sink a company). I work at a VR company at the moment and all of my ex-games industry colleagues are relieved to be out of the industry. It can certainly be fun as a new graduate but as you get older your priorities will likely change. Of course there are studios who really care for and look after their staff, but these seem to be in a minority in the games industry. As a graduate you probably won't have the luxury of choice and will have to seize any opportunity that arises.
A CS degree would take you towards your goal - it's the most requested course in graduate game programmer job advertisements (followed by Maths, Physics and Engineering). I rarely see companies requesting games degrees. A games degree will put your CV into a pigeonhole that targets a single industry, yet isn't even the most desired degree by that industry! There are way more games graduates than graduate positions in the games industry and some of my colleagues at Abertay didn't make it into the industry or only got jobs as manual game testers. And that's before you even consider all the CS grads and other grads that you'll be competing against! Games development is one of the most technically demanding areas of programming and you will face stiff competition for jobs - you need to be hard-working, passionate, and talented in order to succeed. And if you don't make it with a games degree then there isn't really a plan B.
I'll leave you with some advice from Frontier Developments:
GUIDANCE FOR STUDENTSDo you want to become a professional game programmer and you think Frontier might be the place for you? We value both strong academic achievements and proven practical skills, so we'd encourage you to pursue a good education while building games or technology in your own time.A-level or diploma studies in computing, maths or sciences are recommended, but we value diversity and rounded education so don't hold back from pursuing your interests! We do require a degree or equivalent qualification in a subject that involves lots of programming. We strongly recommend the more rigorous academic courses such as Computer Science, Mathematics, Physics or Engineering as offering the best grounding for a programming career with Frontier.https://www.frontier.co.uk/careers/programmer-application-guidance#id_first