It's quite good in some ways, and I found much of it very charming, I think is the right word. The graphics, the sound, the voice acting (esp. Joey until he became Ken) - all have a fun retro appeal. I played a lot of Humongous Entertainment (Pajama Sam, Freddi Fish, etc.) back in the 90s as a kid, so adventure games hold a very special place in my heart. I'd love to design my own someday, if people don't mind a non-complicated level of play.
Nevertheless, it's still very tough at times to play without a walkthrough, and in this instant gratification world of today, not many people are going to be willing to try every little thing to see if it works. There needs to be more of a logical connection between point (or action) A and point (or action) B, even if that means having the characters /nearly/ say what needs to be done. (Not quite, but close so that a lot of time isn't wasted.) That may mean getting less gameplay time for your money, but who cares? (Esp now that this game is free, it's a moot point.)
Another idea is to have the most important points automatically written down about certain characters, like an outline, so that if you find or see something you can search for the key word and figure out /how/ you could use it. That wouldn't necessarily work with, say, [SPOILER] using dog biscuits to launch a mutt into the water to distract a guard [SPOILER], but something like that today wouldn't fly anyway. Imho, that section could have used some reworking, more hints (as in Foster saying something to the effect of what he could potentially do there), or just something different. (Pixel hunts - putty and tongs for me - are silly too.)
I think adventure games have a place today, in a niche crowd, but maybe some concepts need to be dumbed down so you don't need to spend a lot of frustrating time wandering about wondering where to use what on what. :P