Been engrossed in eternal the last few days, didnt even check this site, sorry for slow reply.
To those asking about eternal, it shares more in common with mtg then hs. Its like they decided to re-design mtg for the digital age and took some cues from things hs did well.
Ex: if you just had a main phase, attack phase and 2nd main phase in mtg, thats what eternal does. You can only cast 'fast spells' in response to opponents spells, when attacked, or at end of turn. Removes alot of the unnecessary complications of priority while still giving you options to respond to stuff. Id say 95% of the instants i cast in mtg were at one of those points anyways.
They use a land/mana system, with a tweak. You play mana, and use generic mana (they call it power) to cast stuff. But, there is a secondary cost to most stuff called influence.
Ill use mtg examples, if you have 2 mountains and 2 swamps in play, you have 2 red and 2 black influence. You can cast two RR spells off of that then, you dont use up your influence, it just checks you have enough played. It really helps against color screw at least.