gaslouk,
Adding a choice for the 2 player game of playing 1 or 2 colors is a very good idea and have used that option in other games I made. However game rules do specify using 2 colors each for the 2 player game, a Youtube video on how to play the game does mention that option. I will probably modify version for that option.
The three concentric circles and the circle in a row (small, medium, large) are actual winning patterns according to the rules, but 3 random diameter pieces in a row is not a valid winning combination.
The rule sheet does mention an option for points:
Otrio Extreme!. Play a series of games and giving 1 point for each game won till someone reaches 5 points.
Also deducting 1 point for each player who failed to block the winner.
That last option is very interesting; a player may see winning pattern coming up and chose to work on their own pattern instead, forcing another player to block, if they see the pattern.
I pretty strict about sticking to the rules of a game, but I usually consider adding the game variations for the players to choose at the start of the game.
You can email the changes you made or post them here, if you want.
Thanks for the input.
Donald