Thanks for the feedback.
A. Is this on Mac or PC? Have you tried changing the graphics quality settings? I haven't tested much on different kinds of hardware, so any feedback you can provide is helpful.
B. It's possible this is due to frame rate, as you mentioned. The crosshairs turn red when you're within range to use the claw. Using it when the crosshairs are red should mean it's guaranteed to connect. This is definitely an area that could use more play testing.
C. The enemies are actually supposed to respawn after reloading the game or after leaving an area for a while and then returning. Similar to the classic Castlevania/Metroid games.
Thanks again for playing and providing feedback!