Follow the guide below to check your configuration.
http://www.tp-link.com/en/faq-205.html

Looks like it's all configured correctly and just doesn't work. I have dynamic ip so I am using my ethernet local connection IPV4.

I have dynamic ip so I am using my ethernet local connection IPV4.
Did you refer to Local IP Address?
What are you opening ports for?
Why do you open ports?

Yes, local Ip adress.
Multiplayer game.

I discovered few interesting things. I tried to check ports with program PFPortChecker. It told me that ports 443 and 80 are locked by some application, that turned out to be a skype. After changing skype settings, I successefuly tested all ports and all of them are open in PFPortChecker. However - when I tried to check those ports in telnet, all tests failed.

What's the error message?
Did you enable telnet? Start—>Control Panel—>programs and Features-- Turn Windows Features on or off---Select telnet client
How did you telnet? telnet LAN IP port or telnet WAN IP port?
What's the hardware version and firmware version of your W8951ND?

Yes I did enable it, otherwise I wouldn't be able to even execute telnet command.

"Impossible to establish connection on port 80: Connection did not succede" (my system language it's not enligsh but that's direct translation)

I tested all other ports. I tested both adresses, it did not work on any of them.

Hardware version V.5 (I think that's hardware version), Firmware:[SIZE=3] [SIZE=2] 5.0.0 Build 141114 Rel.26463, which is newest[/SIZE][/SIZE]

w8951nd V5 doesn't support NAT loopback.
If you telnet WAN IP port, it won't work.
If you telnet LAN port but it doesn't work, you should check device itself.
Anyway, ports should have been opened.