First it's fun, fast upgrading, leveling, and collecting. Then progress evens out as you open more and more making it enjoyable. Around 200 slows way way down but unlocks more more more and more. Level this this that this this that just on one character, still gotta lvl and resources, plus this that more more more and you gotta collect the same cards again again again ECT... Just gets overwhelming and pay to play at that point. it's a game you play a little and stop.