Hey, I played your game:
Hey! Thanks for playing it!
I'm not really good at making tutorials yet, sorry for the confusion.
When the round starts you choose one of the 3 cups. Depending on what difficulty you play on (the skull icon in the menu) you either go first when getting the red ball(normal mode) or you go second when getting the red ball(hard mode). In general you want to go second, as you can then react to what your enemy is playing.
Every card starts with 100 power and a gem with a color. The colors indicate what attribute the card has. Green is strong against yellow, yellow is strong against purple, purple beats blue, blue beats red and red beats green.
The one who wins the round gets a power point. If both cards have the same power and none of the attributes is stronger both get a power point.
In the bottom left corner of the screen is a button which also shows you how many power points you have. If you press on said button you can upgrade one of the cards in your hands as long as you have at least 1 power point. Cards can be upgraded a maximum of 2 times.
When going first it's better to play an upgraded card as to raise your chances of at least getting a tie.
You can win by either winning 10 matches or by having 3 cards with 3 gems (upgraded to the maximum) on your hand at the same time.
Unfortunately the enemy code seems to have some problems so there might be a black screen at some point. Haven't yet figured out what exactly causes this problem.
Hope this helps!