Duel of Champions is a good strategy/card game.
If you like MTG this is a nice alternative to MTGO as it is F2P.
Note that DOC uses a open and a standard format.
There is also a weekly format(which often breaks one rule at a time) for more fun.
I will just list the pros and cons so you can decide if that game is for you.
- There is a simple single player/campaign mode (not a single player game so do not expect that mode to be improved/developed) that gives you a lot of reward as you complete it. It also teaches you about a bunch of mechanic and of how strong some cards can be (do not be afraid to make a deck specifically for the campaign and for). Note that the campaign is open format.
- The quest system is nice, it gives you 3 quest each day to do. If you don't do your daily quest one day you don't "lose" the next day's daily quest so you can skip one day if you don't feel like being too hardcore on the game. The next day's quest will be are given as you complete each quest that you had left.
- This is a digital card game so cards are subject to change (which prevents most uninteractive combo decks from being played too long).
- The Altar of Wishes is a place where you can exchange Wildcards for a specific card that you want.
- The Infernal Pit is a place that allows you to sacrifice some of your cards to get some gold (recently you also get some Wildcards) and a chance to get the card the is shown (it changes every 8 hours). Note that it is possible to sacrifice enough cards to get to 100% chance to get the card and it is recommended.
- There is a refer a friend system that gives you a starting deck for each faction (you only choose one when you start) so don't forget to get a friend's referal code or just go on the forums and you should find someone's code or just ask. This will greatly help you with the infernal pit and to start out.
- There is a lot of keywords and mechanics that you will need to learn in order to avoid mistakes which makes the game more a little bit like playing MTG except that after a month you should have seen all of the keywords.
- Once you get enough cards you should not try to complete your collections, instead hold on to your gold until there is a promotion(sales on booster/selling special booster, ect...) or that you need cards to sacrifice to the pit for a card that you want. This is just a warning since I am not sure if it will happen again soon.
- Open format is "unplayable" if you intend to keep playing for free as you will need more than the cards you can get at the infernal pit and from the campaign. To get more open cards from the shop you need to spend money get them and the open format does not seem to get a lot of balance changes so I suggest that you stay away from open.
- Some cards can not be obtained without either buying open booster or using Wildcards in the Altar of Wishes. This is not so bad as the older cards that are available in standard are not a must, you can use some other cards as substitute until you know which of them you want.