Interesting game, had a lot of fun playing it. My keyboards arrow keys are really small so it was a bit of a struggle, but that's not a fault of yours.
The WASD for looking around did help in some levels, but I think it helped a bit too much, making it a lot easier to find the hidden gem, I think without it, it could of forced the players to learn from their mistakes more or maybe some sort of cap on it, or cost, like reducing more time that you have left.
I didn't play all the levels but the ones I did, the exit is where the player started, which worked well, but for some, you could of placed it in different areas, to force the player to go to, since sometimes I was able to just avoid them.
I really enjoyed the strategic element of placing creates to help reach the goal. Overall the game was really well put together with just some small things that could be tweaked to bring it to the next level.