I'm glad to hear you enjoyed it! :3
I personally think I wasted an opportunity with the one Caco in the level but I thought it looked neat there on top of the steps so didn't change it. =P
EDIT: Oops, looks like there are some bugs I missed out on cleaning up.
Once you cross the Red Key bridge in the cave, the bridge sinks into the lava. At this point, if you fall into the lava and use the teleporter to get back up, you'll find a Teleporter pad has opened up in the wall, which is supposed to teleport you over to the side with the key. But, uh... it doesn't actually work.
Also, once you get outside the fortress, the steps leading out are actually too high to get back up and inside. However, this shouldn't be a massive deal as there's usually nothing else inside once the player gets this far.