Klik & Play was good when it came to the basic stuff. The problem is: No game programmer worth its salt will stay with the basic stuff, and Bouncing Balls just won't cut it.
Maxis couldn't even implement
gravity on the
damned balls, for
chrissake.
About every single feature of KNP had a very noticeable and annoying bug. Sidescrolling entities could stick to the ceiling if you held the jump button. Balls liked to bounce in ludicrous angles. The engine could only play MIDI music, and if it was meant to loop... the program froze for a couple of seconds, loaded the music again and started playing. Not to mention that, if you wanted to use values from one board to another, you had to save them in Player 2, 3 and 4's score values. Yep.
In short: KNP was a good idea in a bad package. Its progeny, Click & Create and The Games Factory, didn't fix the old bugs and included new ones (The most horrendous scrolling I've ever seen in my life).
As of now, if you want to make games, you'll have to ask for non-mainstream help.