The rock paper scissors system unfortunately was hated by new players of Alex Kidd.
That's why in SEGA AGES version they put spoiler in the top and bottom of the screen what rock/paper/scissors we have to use against the bosses in sequence.
But for card games I think it's still be fun to play.
Rock, paper and schissors in Alex Kidd was unfair given you had to learn the patterns by blind luck or death.
If I were to reboot Alex Kidd, I would introduce two new martial arts to compliment Alex' Shellcore style. Bladecore and Fancore.
Each core technique is based on rock, paper and scissors and certain enemies and obstacles require the right core technique to deal with them.
As for the card game in mind, that's more lengthy to explain, but the idea is Alex Kidd may visit saloons and sit in games that play this card game for prizes.
