Hi PaceUK,
I've a little experience with arcade sites myself so I thought I'd chime in here and give you my opinion
Firstly the look of the website is ok, the main header could do with being replaced with something a little more professional looking, and either made smaller (height-wise), so that you won't need to over optimize the image too much as it is now, it's quite pixelated, and looks a little rough.
With any new arcades being created now, I would advise webmasters too make sure they have some title text, just below the header, since we all know google now dishes out penalties for lack of content without the user having to scroll down, and it wouldn't hurt to include keywords you are targeting in this content either. This is not a MAJOR deal as you haven't used too many ads so it would be unlikely you would get a google penalty, but better safe than sorry ?
I'm liking the features and navigation, everything is easily found and loading times are fast, so good work on the most important elements !
The only other bit of advice I could give is to maybe think about showing or providing information to users on the benefits of registering with the website.
Overall I think you've done a good job, so good luck with the site
Edit : Oh and just quickly, if your TD section is short for Tower Defense, I would maybe think about actually using the full keyword, since you could be potentially losing out on those looking for Tower Defense games.
