I did a speedrun of this game.
I can't imagine playing this game without checkpoints. I'd probably have given up.
Some sort of warning as to when the vertical zapper things are going to turn on would make this feel more fair, I think. Without that, you just have to memorize the pattern, and also know that rooms reset when you re-enter them.
This is awesome!
Regarding the vertical zappers, do you mean those in the reactor? If so, there are four lights (or crosses when unlit), basically when they start lighting then the zapper on that side is about to come on, just as youll see all four lights go off when the zapper on that side goes off.
If you mean zappers on other screens, those are all predictable, just not necessarily all the same timing. In general you can stop between each zapper but it's slower.
That was a really good run until the bad ending. To clarify, if you lose all 3 hearts after destroying the reactor it's always the bad ending. Generally I found the best reactor pattern is to go left, bottom, right, top, because the left and right vertical beams are slightly out of sync and you enter from the left so go there first. I'm sure there's an even better pattern though, without wasting time waiting on the sides.
I spent some time trying to optimize the reactor, and I wasn't able to find a better order, so that's what's in the record now. Also, today I found this amazing skip (will upload a better any% run with it soon): https://clips.twitch.tv/madewokherd/CrazyGaurStrawBeary
I also saw you damage boosting in other rooms. What you could try, because getting hit always knocks you in the opposite direction to the way you're facing (and up slightly), is right before turn away from the thing your going to hit or back into it while drilling, that way you effectively get knocked into the direction you were moving. Not sure how effective it can be in a speedrun but it's something to try.
