Another advantage to using the code above is you get all content unlocked for some time. Unsure on how long though.
The game itself is a dead simple game, it's 4v4 turned based PvP. Everyone picks their own hero with its own abilities and its the first to 5 kills, or the most after 20 turns. Average game length is around 15 minutes so it's not overly time consuming.
The Heroes work on a rotation like other free to play games, but the only way to permanently unlock them all is to purchase the full game which is currently £22. This unlocks all content apart from skins, which can then be bought via a chest system or simply unlocked by in game currency. The only downside to this is that you need to have purchased the full game to play ranked, but most likely you will have decided to pick it up anyway of you've played enough to be ready for ranked play.
Since it can be played with just a mouse it's also a 10/10 game for streaming to a tablet.