I really like the game concept.. a game inside a game.. it sounds really fun. The conversations between characters was also really good. I like that every characters has their own special skill, so that they are all useful in their own way when exploring and passing challenges. 
The puzzles seemed interesting too, I was only able to finish the first two though, in the third puzzle (with the fire imp) I got an error "TypeError undefined is not a function", it happened only after I was able to use the shield skill to get my character to the other side. When I pressed q or w to change character I get that error. I was able to change characters when I entered the puzzle stage tho. 
I also think you should make the 'ghost' guy solid, I kept running through him even when I wanted to interact with him, actually I didn't even realize at first he could tell me how to solve the puzzles.. lol
Overall: It was a cool game! I'm really liking the look of it and it's too bad about the errors. I hope you'll fix this as soon as possible so I can give the game another try . :P Keep it up and good luck!

This game does not offer a big plot with twist and turns, it's pretty simple but what it does have are some really smart and challenging puzzles with likeable characters, I'ts kinda weird since I'm usually pretty good at bird-view 2d puzzle adventures but this time I was stuck trying to figure out an obvious solution,the game is kinda short but it depends on how much patience you have on puzzle solving, it starts really easy and then hell unleashes, the puzzles give that kind of sensation you get from games like portal even to the point where once you completed that one that's so hard the satisfaction is amazing
Now there are still some things for example the issues while trying to download the game (Updated version) or that the music does get kinda repetitive after a while, but overall I had a real challenge over here

Alright, I took a shot at your game. The basic premise seems good; reminds me of Knights of Pen and Paper on Steam. You have four characters, each with distinctive abilities and personality that you need to utilize in order to solve the puzzle rooms you encounter. You have the Knight, John, who applies a shield, or a barrier, that blocks any incoming projectiles. This is mainly used to safeguard others. Then, you have the Berserker, Shemri. She can jump over 1-square obstacles and voids. You also have the mage, Cherry. She can blast most enemies (and your party members too, if you're feeling evil) away with a single shot. Some enemies are immune to this. Also, her fireballs can trigger switches if nothing else is on the way. Then, you have the Bard, Aubrey. His ability is the one you'll probably end up utilizing the most. His musical notes that he shoots switch placements between Aubrey and anyone they hit.

The puzzles start off as easy, but quickly become progressively more difficult. Most of them are genuinely intelligent. I wasn't too keen on the jumping puzzles later on, read more on that below.

The game shows some real promise, but a few things I feel like I should comment on. For starters, maybe you had a tutorial of sorts ingame, but if so, it was hidden well enough that I did not encounter it. I almost stopped on the first puzzle that required jumping as I did not realize (at that point) that the characters had distinctive abilities. Also, the special abilities are triggered via Shift, which introduces another problem: Windows' default behaviour is that when you rapidly press Shift multiple times in quick succession, you get this annoying pop-up that asks whether or not you want to utilize the StickyKeys feature. This in itself might not propose an issue, but since many puzzles require a lot of jumping (done via Shift), the popup was constanly interrupting my game play. When paired with the fact that some of the puzzles required rather exact timing on their jumps (Stages 10 and 12 come to mind) I had no other choice but to exit the game. If you somehow manage to fix this in future versions of the game, let me know and I'll play it again.

Notice: I played the updated version linked on the main game page, as the author is aware the version linked above is broken.