tl;dr - 9.5/10 game.
The game is visually pleasing. There may be a few small clips or graphical problems, but the game runs very smooth, since it does not have fancy shaders or modeling. Audio is fine. Background music is satisfactory, and the sound effects are very good.
PVKII is a VERY good idea. As the title states, it is a three team battle. Pirates VS Vikings VS Knights. All the teams have three classes, which normally are: Ranger, Melee, and a medium-ranged fighter. The game is well-balanced, with many counter attacks you can make against other players. The community is amazing! The developers are awesome!
PVKII is a FREE game. It's not filled to the brim with microtransactions like other "free" games. In fact, there is nothing to buy. (except HL2 to play the mod ) The game is very fun. Instead of your normal two team fighting game, this game is perfect for groups with multiples of three. If you have lopsided teams in other games, try PVKII with friends! All the classes are unique, along with the teams.
Amazing, truly FREE game. Very fun three team fighting game! Developers are cool, and the game is amazing! The game itself runs very smooth, with a sacrifice of polycount. (but in an intense fight, you wouldn't care, and it's not THAT noticable as other games)
Buy it when it goes on sa-... wait... it's free! If you do not have the original game (HL2), BUY IT NOW. Play HL2 through, and then play PVKII.
The only drawback is the small community. Otherwise, this game is perfect. You probably want to play with friends though, so you can find people to play with.