Yep.. the game starts to get quite hard at level 10. My advice:
- don't try and run away from the blue wisps (the fishy things). Once they see you, they'll follow you forever, and can drift through walls. One way to approach them is to jump up from below and get a couple of shots in before they shoot back, wait for the bullets to fly overhead, and then jump up again. If you can't avoid their bullets because they are at the same height as you, try dropping down to somewhere closeby where you can continue the process. They take 7 hits. For the first couple, you can also run away by using the windy tunnel to the left. Hit and move, hit and move!
- To get over the spikeys (they scoot left and right and shoot out spikes), try shooting them a couple of times. This will make them angry and they'll stop moving to shoot. After they shoot, there is a pause where you can jump over them more easily. Of course, it's easier to just destroy them completely, but it takes a lot of fruit.
- The weird snowman creature is just before the inn. When you make it up to there, it's sometimes best just to make a run for it.