You can buy some bitters in cans like john Smiths, but its imported and more expensive than Keo/Carlsberg, a lot of bitter drinkers sometimes drink Leon.
The guy that has the shop called "The Beer Sellar" has some interesting ales,it is situated not far up the road from the Seven St.Georges taverna in Geroskipou,I believe he also runs a bar in the Bar St. district of Paphos.
Kozel is not a bad brew as Jim B has said. They do a Dark Ale a bit like an old fashioned Brown Ale and a Premium Ale similar to something like Pedigree.
Aphrodite brews need to be served cold and can sometimes get a bit chewy. I find Leon is little more than a darker Keo,Carlsberg - none of which I enjoy.
Some of the Bulgarian and Romanian beers are a bit darker than the Cyprus ones, and very good. They often come in 3 litre bottles from the Bulgarian and Romanian shops. Ask the staff for recommendations. Relatively cheap too.