well
I liked this game. but I liked portal so thats no surprise.
I see people complaining about the dificulty. I get it. as it took me some time to figure some levels out, however it was not impossible and I got it at the end. I think the problem was the option to skip levels. even seeing a video walkthrough and copiying it in gameplay gives you a tiny sense of achievement, skipping dosent. so next time, take the time to make a walkthrough instead of the skip buton. your game will be better for it.
the controls were a bit sticky at times (thanks for that F key, it really helped!) but all in all it was managable.
the sound was well placed and helped set the mood. so props on that.
now, the whole secret charachters buisness. while amusing for the first two goes. by the time I was playing the whole game again for the fifth time, with a chicken. it got kinda old. if your secret charachters had different phisical attributes (say, faster runing speed, higher jumps, half cooldown time etc) it would give the player a chance to solve the same levels in a different way, which is much more satisfying then just using the same solution 5 times. also if said differences ment one charachter can reach secret places that others cant. well that would just be secret collecting awesome wouldnt it ?
art was solid, no complaints here.
story-wise. while we know from portal and the shift series that this kind of setting works for this kind of game, I'd love to see some more originality. take a chance instead of just cloning past succes. inovate.
all in all I enjoyed your game enough to play it through and get the secret medal, so you did a good job. could have been a bit better. hope you take these ideas into acount when you make a sequel. and you better make one :)