as expected, there's been a number of little bugs surrounding the damage/health change of 0.9.1. a friend and I have been playing a lot of Mysterious Space these last few days in order to identify them.
this latest bugfix - 0.9.1.3 - is the largest, and hopefully the last?? although I would not be surprised if couple more little issues popped up >_>
I've made efforts to preserve save game compatibility throughout these bugfixes (save games for 0.9.1 through 0.9.1.3 should all be compatible), but it's difficult to thoroughly test. definitely let me know if you encounter any problems there.
the full changelog is here: 
https://mysteriousspace.com/changelog/0-9-x/ but  here are the highlights:
[*]orbitals (in orbital co-op) were way too strong after the damage/health change. they essentially had their firepower doubled. I didn't want to reduce the fire rate of the bullets, however, so I did someting weirder: their guns now fire for a full second, followed by a cooldown for a full second. incidentally, Aiming Altair (that obnoxious square that fires EMP bullets at you) uses the same gun, so has received this same nerf… which I think I'm okay with :P
[*]the Shield Rerouter accessory hadn't been adjusted for the new system, and I couldn't think of a good way to make it fit, so I simply removed the item entirely! I've kept the code around, both in case I can find a good way to bring it back, and to maintain compatibility with saves which already have Shield Rerouters in them.
[*]Vampire Shields HAD been adjusted for the new system, but perhaps not enough! with a good Vampire Shield, it was almost impossible to get killed. so they now have only a % chance of granting a bonus shield. (they may STILL be too strong; I'll have to play more to see.)
[*]the red mushrooms were dealing TONS of damage, and were basically guaranteed to straight-up murder you! sorry :| this has been fixed!
sorry about all the bugs in this last update, but I think MOST of them were making the game easier, rather than being murderous (except that red mushroom one >_> sorry again), so I hope it's been a relatively smooth transition.
I'll keep be keeping an eye out for more issues, but otherwise, I hope to start working on next month's release soon :)
anyway: thanks, as always, for reading; and thanks for exploring Mysterious Space :)