Nice game, I'm a fan of deck builders.
Unfortunately they are hard to understand without a in-game tutorial. Not sure the capture card was working, never managed to capture an enemy. Similarly, what are sun and moon cards for?
Thanks for playing! Sometimes cards don't let you play them... not intentional lol If you hover over the enemies, it will tell you what health they need to be at to capture them. Sun and Moon cards are passives when they are in your hand. If you hover over them, they tell you what their passives are. Sun heals you when playing cards. Moon negates creature insubordination. :)