There seems to be no reason or rhyme in how much health is lost in a hit. (and the few times it did only one unit worth of damage it pushed the character into inescapable death anyway)
Yes, that's a bug I'm aware of.
I can and will fix it by adding an invulnerability timer, but the day came to push to publishing before I could get around to it.
Hopefully it isn't that much of an issue for you; I appreciate your patience.
OK, after making breakfast this morning I sat down and implemented the timer. The new version (1.01) should give you a second of invulnerability after contact with anything dangerous, and nothing will do more than a single point of damage.
Thanks for the feedback!