I'm glad you all like those games (Eigomon and the basketball game)
I also use some animal board games to practice comparative and superlative. Let the students travel around the board and compare the animal in the space they left with the animal in the space they moved to.
Ex. If they were on elephant and moved to lion:
Lions are scarier than elephants.
You can get printable board games here
www.mes-english.com/worksheets/flashcards/
I follow up with some talking worksheets on coparatives
http://www.mes-english.com/worksheets/talking.php
Those worksheets aren't games, but they might be helpful.