Retro rhythm-themed mini-game collection Bit.Trip Saga is coming to the North American 3DS eShop on 20th December for $14.99, Siliconera has reported.

To put this in perspective, the game originally retailed for $39.99 when it was released in North America last September. It later came to Europe this March.

It's not unusual for full priced retail games to be sold on Nintendo's online storefront, but it is unusual for them to be sold later at a reduced price ala XBox Live's Games on Demand service. Of course, most Games on Demand titles only match the their current retail value, whereas Bit.Trip Saga will actually be cheaper than it is in stores. As of right now, Bit. Trip Saga is going for $19.99 at GameStop and $16.49 / £9.99 on Amazon, which doesn't include shipping.

Regrettably, this seems to be North America only as Aksys is publishing there, while Rising Star brought the game to Europe. I've followed up with Rising Star to see if it has any plans to follow suit and I'll update if I hear anything back.