Does your VPN support both UDP and TCP?

Yes , it works on both UDP & TCP. Actually it supports both of them when it is installed over a PC OS , but for RouterOS (like Mikrotik) it supports only TCP.

What are the system requirements?

You need just a PC with followings:

Windows XP SP3  or Linux CentOS 5.x Final (full packages installed)
2 NIC (Network Interfaced Card) installed on PC.

Is it absolutely safe ?

Our VPN solution is SSL based and uses a 128 bits key to encrypte data, so it is absoultly safe.

Does it work behind NAT and dynamic IP?

Yes , it works behind most of VPN types as well as dynamic IP.