I have probably played Colonial more than any of the top ranked courses and consider it to be among Texas's best. I don't share Jim Hoak's take on Texas golf- there are many worthy courses here that don't get their due recognition for a variety of reasons, weather and environmental factors among them,
Colonial is a difficult course as it was intended to be played- in the wind, with firm fairways and greens, and snarly bermuda rough. Sunday was more of an indication on how it can play, though I've been there many times in the summer and fall when hitting in the rough was at least a half-stroke penalty.
Another thing that might have contributed to the low scores is the conversion from commom bermuda to 419 (I think). Specially for the tournament before the common had a chance to recover from the winter and the heavy cart traffic (Colonial does well over 40,000 rounds/year), balls would run into the snarly rough or sit down more requiring a heavier hit.
Colonial is full of strategy off the tee in terms of club selection and hitting the correct side of the fairway. The greens are small, perched, and tightly (and deeply) bunkered. You just can't miss on the short side, so one is often just trying to hit the middle of the green.
The greens themselves aren't heavily contoured, but the breaks are there and they're very subtle. When it is windy, which it often is, they're extremely frustrating.
The course is overtreed for my taste in several spots, 3, 7, 12, 15, 18 (particularly before the hanging tree on the left side fell), and they make the conditioning difficult.
Though it is described as a short course, most of the good golfers in the big daily game played from the second set of tees. It is much more than a great club course for amateurs, though its flat terrain, only two par 5s, and a bunch of very demanding par 4s reduces its appeal for me.
Colonial is a great family club.