Tactics will affect the match, so will formation, players etc. Each of their ability will be taken into consideration in the match engine. I have uploaded a demo up on my mates website, if there is any bugs or errors please let me know.
http://www.dansparks.co.uk/thesoccersim
There might be some problems, but not entirely sure because I have been working on this locally, so I have might of missed some parts that might need changing.