In my mind, it doesnít have enough impact for a poster.
Your layout is fine, but itís definitely missing something, in order of getting the audiences attention. You have all this white space in the middle, why not use it to your advantage.
You may want to have a look at your type hierarchy in the information section.
If it is for the Shakespeare play then you might need to bring that into the poster. It doesn't make me think of a play or think of Shakespeare. I have actually worked on programs for our local theater group and one of the one's they did was for this play. They actually do the covers based on drawing of that time period when Shakespeare wrote the plays. An example is the one they did for Richard III was of a hog wearing a king's crown and the robe (cape). Not sure if this helps at all but that will give you an idea of what I am talking about. I think you need to bring in something that is part of what the play is about. Make's it more recognizable and known.
Hope this helps! Good luck. Keep us updated as you work on it.
Everything works very nicely except a few aspects. The left-rag in your information typography doesn't make a statement. It doesn't have decisive alternation, nor does it create any clean shape (like an even slope, or a pointed corner or something). It looks kind of pasted in.
Also, I agree that you should utilize the white space. This type of layout would work extremely well as a business card, because on a BC you have a captive audience...the owner. On a poster, you have approximately 3 seconds to catch a persons attention before they look elsewhere. Try taking a full color picture of a stage with the curtain closed, and placing the yellow line, the silhouettes, and type, and everything inside on top of it, so only the border of the poster is partially a picture of a stage. It would add a nice contrast (full color picture to the minimalist layout), as well as tastefully adding some colorful attention grabbing pazzaz. Plus, you will have to examin the border a little to discern what it's actually a picture of.
Good concept - but I don't think that it has the impact necessary to stand out on a wall of other posters and draw someone in from a distance to read the text. It's as if you took great design elements and scaled them down too much.