When I was speaking of the tempo I was referring to changing it at certain parts of the song. As I said before, I do actually like the pace. I only mentioned that because I noticed it's a common technique to add a bit of variety.
As for the climax, the best way I can describe it would be the part of the song that really makes the "core" song (in this case, the observatory theme)stand out. To me, this can mean making the theme a little more prominent, maybe a little faster at that point. It can also mean that all the instruments chime in for dramatic flare or 1 or 2 main instruments take the stage as a kinda solo. But the climax means the core song gets to be the true star of the show.
When I listen to your song I see a fancy ball bathed in a golden glow. A band playing in the corner while the guests drink wine and chat. In the middle or the room is a dance floor where couples waltz slowly to the music. There are many couples at first. But around the middle the crowd begins to part allowing the spotlight to shine on one couple. A couple whose dancing steals the show. They waltz and spin in sync with each other, feeling as though they are the only ones in the room. This is where I imagine the song reaching it's climactic point. The music becoming dramatic and prominent as it reflects their love (man I watch too much tv lol!)
I hope that I explained this okay. Unfortunatley I'm terrible at articulating my thoughts . I honestly can't offer any technical help. I can only try to explain how I feel when I hear the song. Hopefully someone with more musical experience can chime in instead of all these wishy washy feelings of mine lol