I've prevented the Eclipse.
That was an intriguing use of the theme and the game worked better than I thought it would after the first few fights, it gets fun as you and probably even more as your enemies get Sun/Moon cards and deck modification choices become quite non-obvious.
I think the game contains the right amount of content but it's every part of it is a bit too slow which is the reason why it drags a bit.
It was fun, anyway.