Thanks for the quality feedback!
You can speed up the game with shift, that is explained on level 3 iirc. As for the later puzzle levels, I totally get where you're coming from. Difficulty was hard to get right, the rank system was meant to allow for less concise solutions to still work but it seems it didn't work for everyone.
There shouldn't be any RNG, I think there is a text box that says that nearest the attacks are targeted first, although I regrettably forgot to mention that once something is "locked on" it won't change targets unless the attack is destroyed. That part is poor tutorialization on my end, and it made later puzzles seem less intuitive that I'd hoped.
Glad you could still enjoy it despite some rough edges here and there.