Pros
Recognisable brand Online Gaming company Central London location - good if you like to be surrounded by tourists and expensive places to eat.
Cons
Low salary and almost no benefits - they will try to sell you the team events instead. No career progression, some really average technical people and a few really bad apples there. Lack of direction - was hired to work in a particular project just to be scrapped a few weeks later. Old technical stack, it's like working in a factory. Be ready to be a yes - man and keep your head down coding. Don't worry another dev will take your place soon enough. Don't believe the good reviews, I'd say 90% percent come from HR or Dev managers, they are just not true, find people in your network that had worked for Gamesys. They are struggling to get some talent and people are leaving all the time or being fired for any reason - they would say they left overnight. Not true.