The Wizard of elemental magic

I think my solution for level 13 was...not what was intended at all. I got the fire golem stuck in the spike shaft. I know I was supposed to melt the ice so he patrols off to the left, but there didn't seem to be any way to get back up top without it, and there wasn't enough time to grab the earth magic and beat him to the ice, so...

There is another solution to Lv 15 by going through the bottom left door first: Get key, open bottom left door, get past the blob using the platform, get Ice spell, build a 5-6 block ice tower, go up, drop down and grab everything but DON'T OPEN THAT DOOR (say that in Barry's voice). Instead go back where you came from and to the starting point using Ice blocks. Open upper right door and grab Wind spell, then open lower right door, burn blob when it's in the far right corner, fly up with Wind, drop down through the ghost with Earth, then wind your way up to the top and drop through the flames with Earth. END. Maybe that was the "intended" solution but the beauty with games like this is to also find alternate solutions that allow you to shave off just a couple more seconds in Time Trial. Good luck!

So we had:The ranger and the wizard, next one the warrior ? :P

Spoiler Level 12
I normally don't comment here but as I was unable to find any walkthrough for diamond on level 12, it's just jumping towards it after you turn off the fires switch. It's a tiny maze but easy to figure it out once you're inside the block. Cheers!

Solution to level 13: First, use fire magic to get the crystal by the bee. Before unlocking the door, melt 1 level of the ice. Hop over the fire monster and grab the earth scroll, then quickly jump down using earth before you land. If timed right, the monster will melt the rest of the ice only to immediately bounce off your statue, heading back towards the ghosts. This gives you time to jump down the hole in statue form (I actually fell through on my initial jump down from where the scroll was, but the monster still bounced off me once on my way down, which is why pre-melting one layer is useful), hit the lever, and make it across the mini-pit before the fire monster makes it down. From there, it is a simple matter to use the earth magic to slowly push your way to the right and climb, then grab the crystal after the slime has left.