When playing any type of OSR/OGL game I pay close attention to Saving Throws. They're not a casual thing in my games, players often need to roll them and failing them can mean something really bad happens to a player character.
I do think low-level characters should struggle somewhat with saving throws but as they level up they should get to feel a bit more confident about them overall.
I think 'Machinations of the Space Princess' is a good OGL game but I have an issue with the saving throws. The way they work is that you take the related Ability Score, divide it by two... and that's the target number you have to roll under.
That means that someone with a Strength of 18 (!) would have to roll a 9 or under to succeed a Saving Throw. Yeah, dudes who are as strong as a beginning Human character with no cybernetics can get... have a less than 50% chance at succeeding on an unmodified Saving Throw. Not the end of the world for a low-level I suppose, but those numbers stay the same as you level up unless you put skill points into them. Skill points in Machinations are skills, feats, class abilities, saving throw advancement and ability score advancement all rolled into one, and some classes get very few of them. That's just a bit too harsh in my opinion.
When I house rule something, I like to not have to change what appears on the page. That is to mean, I don't want to have to recalculate NPC stats because my house rule is different from the official book, I prefer if possible to do it in a way that doesn't give me extra work when reading material and using it at the table.
My solution in the end was to use modifiers to the existing target numbers and then roll under those modified results, that way I can still use the same numbers as the book and fix my nitpick with the rules as they are. I made it so someone with a target number of 5 to roll under would have a 50% chance at a Normal roll. (So it's 5+5= Roll 10 or under.)
Very Easy: +15
Very Difficult: -5
Inhumanly Difficult: -10
Thoughts are welcome.