Iuliana,
actually, your plants look good!
the browning/blackening of the VFT leaves looks like perfectly normal "leaf old age" to me..
as individual leafs and traps get older, they simply turn brown or black and die off..as long as newer traps are coming in to replace them, there is nothing to worry about..once the leaf is more than half black, you can just cut it off..(as long as the plant is healthy, you can cut it off any time really..)
looks like you are growing your plants outside? that is good!
outside is MUCH better than inside for VFT's and Sarracenia..
I just googled the climate of Romania..looks like you have fairly cold winters..looks quite similar to my climate actually!
If the majority of your winter days are spent below freezing, you will need to create a safe place for winter dormancy...there are many methods those of us in Northern climates use to keep our CPs sleeping comfortably through the winter..check out my web page (link in my signature, below) for some ideas..
So far, looks to me like you are doing things fine..are the plants in peat moss? how much direct sunlight are they getting? and what are you using for water?
Scot