My problem with the series is that most of the games seem very shallow and not altogether fun. For the record, I think Dotstream and Orbital (planetary Katamari Damacy -- how can it go wrong?!) look to be worth the $20, so I bought them. Both these games have a very clearly designed level structure and set of objectives; their gameplay is easy to figure out from watching them and of sufficient complexity to be central attractions.
Boundish:
I still enjoy Pong -- a great deal, in fact. I won't pay $20 for it no matter how many skins are available. (And no Breakout-like mode? For shame.)
Dialhex:
Looks like a fun concept, but from what I've seen it's very straightforward and purely geometric. The classic arcade games we remember generally had a great art style (Joust, Asteroids, Battlezone) and a fairly complex set of interactions -- not the case for a straightforward, geometric puzzle game that could almost be created in reality.
Digidrive:
I may totally misunderstand this. I've watched all the videos since the first announcement, and as near as I can tell it's a game in which you direct traffic. It almost seems like a retarded version of Chu Chu Rocket. If anyone understands what this game is and I'm wrong, please explain it!
Soundvoyager:
This may be a victim of unwarranted anticipation. I had visions of a music-based Rez-like game with game objectives similar to Star Raiders. (Don't ask me why, I just did.) Instead, it's a bunch of sound-based minigames that test your auditory spacial perception. The graphics are literally dots.
Coloris:
Another victim of anticipation. I thought it would be a Lights Out clone, which would still be shallow (and there's already one available on the GBA), but instead it seems to be a dumbed-down version of Bejeweled (or the puzzle mode of Zookeeper). I'm not sure if it's more or less dumbed-down than the original, but it doesn't look very promising.
So, yeah, I agree, they're stylish and have nice boxes. But will you play most of these for more than a week? Will you be playing them three months after you buy them?