Thank you so much for your feedback :). This was the first time I tried making a puzzle game, and there were many design choices that were not well-thought-out.
My idea was to show the player in the second month that when there is more than one positive property in the enigma, the player must choose a card that contains both properties simultaneously. But looking back, it becomes tough to guess that's that case without prior knowledge since the game doesn't do much to explain that to the player.
Thank you again for sharing your experience, I now see that I should have designed the gifts differently, to express the game mechanics better to the player. I will take that feedback to heart and try to improve on the front in the next game jams I participate :)