It's definitely an interesting game, with an interesting character change mechanic. But, I would like some riddles or puzzles that could be solved by a combination of knights. (my opinion)
It would also be interesting to add a limited number of knight changes, a cooldown or something else so that the player has the "weight" of his actions! The game feels too free...
But I can't say it's a bad game. I think this game is very cool, and that a good job was done in 3 days! :)