How Good is Good Enough?

[TheGreatCthulhu]

Actually, many people in various fields ask themselves the same question, especially in areas like art or engineering. I mean, it's not uncommon for people to want to fine tune their creation some more, or add to it some new and cool features, simply out of commitment to quality and love for their work, but often there's really no end to it. You can always improve something, and it will always seem like adding a new feature could be a really good idea. If this spins out of control, you may just never finish your project (also, deadlines get broken, you have feature creep, lack of funds or other resources, etc.).

This doesn't mean that one shouldn't strive for quality! Quality is important! But it does mean that you need some kind of a plan early on.

In your case, for a CS, think it through a bit, and figure out what are the most important aspects of it, what kind of experience you want it to be, what are the most necessary resources to achieve this, how many levels you want, how many is reasonable, how much time you have, etc..
Basically, prioritize things, and figure out roughly what would the completed CS be (but, realistically), and then work toward that.

Spend your time on things that matter the most, and do the less important things if you find room for them. For example, put the most effort in the areas where the player is going to spend a lot of time, and put less effort into hallways through which the player is just going to run through in fear. Or concentrate on the major story points first, and add the less relevant detail later on.
Of course, what is more relevant will depend on your ideas, approach and the CS itself.
Set yourself a milestone or two (like, milestone one: if the game has these things, it is a decent game; milestone two: refined enough to be released, etc...).
You could even release new content after your initial release (new levels, better textures), as a sort of a patch.

Also, you could ask some of your friends how the CS feels. Do they feel that it needs more work? Make them tell you why, and in what areas.