The recently-English released Digimon TCG has a lot of interesting things going on, but one thing I can't determine just from reading card effects is how viable multi-colour decks are. The game footage I've watched is completely dominated by single-colour decks that work towards getting out a single level 7 Digimon.
So, is building a deck around using two or more colours viable and what are the implications of that on how you can play the game?