Multi-Disciplinary Designer: Former ACD at DeviantArt, Design Lead at Vidy, and Chief Creative at murderloft. Free Agent. I make things and have opinions.
Great critique! Sorry I didn't get to it soon enough to be posted! I honestly didn't know these things expire!
As for that building, that was in the original photo, but you couldn't see the outline of it or the sky at all, so I wanted to make sure the skyline was reflected in front of the sky to enhance the depth. I could have certainly removed it as well as the rest of the skyline and built a more effective landscape in its place
I like the colors and the shape even though it's really an altered ring. I'm not entirely sure what the company is (the website doesn't exist, and no description was provided), so I can't be sure that it fits what the company does. It reminds me a little of the BP (British Petroleum) logo. It's green / yellow green and circular in shape. It also mimics a sun in some ways, so I'm sure you can see why I connect those two logos.
As far as the shape goes, I'd say that it looks nice in this presentation, but at small sizes, the points may become abstracted.
The name "Dulcet Opportune"... I don't know what language that is (my guess is French), but that's not really as big of a deal as the font used. It appears to be Century Gothic (and I could be wrong about this). You may or may have not been able to choose another font for this. If this was for a client, and they requested you use that font, then I understand you using it. If you had no other fonts, then I could also understand you using it, however (and I'm sure you're aware of this), there are other fonts out there. On that note, I would have liked to see a less-used font implemented here, but it does fit with the design you've got. Just a matter of taste, really.
For the card layouts, on the front (logo only), I get the placement, but it doesn't make the card stand out all that much. A brighter and bolder design here may have worked a little better.
On the back (information), I totally get where you were going with this and I applaud your effort. The text is laid out in a way that's relatively easy to read, but there are 2 things that stand out to me. One being the weight of the text itself. It may become hard to read when printed if it's very thin. Also, there's no hierarchy to the text on the back making the information all look the same. In addition, the address, phone numbers and web address are all stuck together. There's no visual breaks there which make it all lump into one object.
The logo usage on the back is nice as far as placement goes, but it's very bright and stands out quite a bit compared to the information. On that side of the card, the information is the most important part, and it should show. The logo could have been set at about 15% opacity in a single color, and it wouldn't draw visual attention from the information so much.
Overall, I like the ideas behind this, and also the effort. I can see that you have a refined taste, but in my opinion, there needs to be just a little more work on this for it to really be "there".