Science found out (this entry tells you - I write the truth - so don't debate with me
)that the time when you had the most testosterone and hormone coctail, as a male was 14-18 or something like that. (for me it was 21-27 as a late bloomer
anyhow back to science...) We always knew that but these hormones play a important role when it comes to remembering history, it makes a very strong connection.
btw: recently neurology found out that you have more brain-cells-like connections in your stomach than in your head, and the stomach plays an bigger role for thinking than we thought 20 years ago. (rumor has it that male stomach when it is growing and there is no place in the head so when men get old the part around the waist is used for increase/growth.
... but back to science)
So when you see a game you did not see for 10 years - you are getting thrilled because you remember the "Activity Level" that you had back in those days. (and this might be true if you talk to older people - they say - they once had more energy - and this is because of the hormone change - but they get in touch with children they say "I feel young again" ... but back to games....) Even games that you felt - they were OK - the feeling is now GREAT seeing them again. I think (not science) this nostalgic -WOW effect - is only the first few times because then emotion is overwritten over time with the level of hormone you have these days and the effect wears off (plus you might be used to a different level of visual stimulus these days). However there are good reason to keep playing the game, for example some of them are good. (at least I think so - and it seems I am not alone). Plus I think getting in touch with and "old" part of you - and having positive emotions, was important for humans to hold together the community (clan, horde, pack, family what ever). So this might also play into this.
The same nostalgic - wow - effect - happens in connection to music. People hear music when they are young and they always feel that this is "their" music. True for our parents and for us - and if you cant stand the music of this generation it seems that will go on.....