Thanks for the feedback, justin.
The one with the darknuts in the tight space originally had more darknuts than it does, but it was just too hard. I'm not sure if you have the old version. The latest version has 4 in there.
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The other one, with the goriyas and darknuts, is one you can just continue past if you want. However, you can whittle them down by stunning goriyas with your boomerang, and using the blocks as shilelds as you kill the darknuts, before going back to work with the goriyas. (Note that this has the "ringleader" attribute set on the first enemy (a goriya, as you'd know by the key he carries the first time you're there) so you may very well get out without killing half of them at all). You can also get offset from the goriyas to avoid their boomerangs. Although it's not a necessary room to pass through, it is one that you can use to build up your skills.
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Perhaps I should take away a couple of enemies there.
The gimmick of level 2 is that if it's hard, you're going the wrong way. I could tweak the enemies a bit, perhaps, though. You may need a way to farm hearts through that stretch, as it's deliberately a hard stretch.