Susume! Taisen Puzzle Dama: Tokon! Marutama ChoNintendo 64 Japanese (NTSC-J) Games
Our first reaction to this game was that it was terrible, but we kept playing and found out we liked it. You have to drop pieces down while playing against someone else. If they are square, you need to make a ball beside it disappear before it is eligible to be eliminated. Balls eliminate if you have enough of the same type touching each other. After spending too much time with it now, it turns out it's great.