Difficult and pointless...
It was well coded and everything, but I think some of the puzzles were just unfair. I hate those "hunt the pixel" puzzles. Looking through the walkthrough, I noticed that I hadn't found the code and the blue tile...And I STILL had trouble finding them, even with the walkthrough's directions. Forcing the player to hunt over areas of the screen doesn't make for good gameplay.
The other thing that bothers me about the game is that there's very little explanation. In the walkthrough you say things like "The Sphere needs more power to continue", but how is the player supposed to get that when they're just playing through the game? They end up trying random stuff until something works, which means they don't know what the story is.
Anyway, it was a good effort, maybe your next game will be better. ;)