Action: I think the fact that the Comedy of Errors is probably better off as a one plot play. The Merchant of Venice had three main plot lines that it followed; the pound of flesh, the caskets, and the rings. However, understanding the two Antipholuses and the two Dromios and everything that is happening within that is enough for one play. So while it does constrict to some degree, I think the play is easier to understand and therefore funnier for the viewers by having only one action.

Place: This unity is a lot more constricting for the Comedy of Errors. There actually are a few main places that it takes place. The house is the place for a few and various street corners are the setting of the rest. There's also the beginning scene in the Duke-guy's place. Although it does stay in the same city, it would be easier to portray on-stage with differing set designs. It could be done, but it's the most troublesome of the three and makes viewing the play difficult for the audience.

Time: I think this unity is one that really guided the Comedy of Errors. The beginning scene really sets the time period for us. The father is going to be killed that evening if no one comes to pay his due. Obviously this means the play is going to span up to that evening and no longer. It will stay in the less-than-24-hour range. It does limit the play, but for a good reason, almost like Shakespeare was setting himself a limit of time. It fits and works well, making the experience more comfortable for the people watching.