Russ-Admin I "made" Hostile Space for the same reasons as my motivations for making my current-day apocalypse Borg-hack, Human Remains: a) it's more fun than not doing it, and b) I didn't have a game that fulfilled my needs sufficiently.
Have you played Mork Borg or any of the many Mork Borg-derived games (Ronin, CY Borg, Human Remains, Pirate Borg, Death in Space, Cthork Borg, and others)?
They are typically enjoyably/absurdly over-designed, with neon colours and a million different fonts. Lots of fun, but luckily art-free/barebones versions are often available to download for free from the games' various websites. I use the barebones version at the table, when I have it.
They are d20-resolution based. One rolls PC stats with 3d6, but only the modifier is recorded: so your Strength is somewhere between -3 and +3, for example. Resolve all actions (combat, saves, everything) by rolling d20 and applying the relevant ability score as a modifier. Roll equal to or higher than the target Difficulty Rating (DR). The standard DR is 12 (but it can be raised or lowered to reflect particularly easy or difficult actions).
Those are pretty much most of the rules, basically.
Abilities are called different things across the different Borgs, but they tend to boil down to the following five stats. Strength (melee attack, lift, push etc.), Agility (defend, jump, finesse etc.), Toughness (one stat for saving throws, more or less: endure, survive etc.), Presence (ranged attack, display willpower, observe etc.), and one other game-appropriate mental stat: Spirit in Pirate Borg, Knowledge in CY Borg, or Tech in Death in Space, for example.
Tons of fun random trait/ injury/ off-putting habit tables.
Armour does not prevent hits: it subtracts damage from successful attacks, but the heavier the armour, the more difficult Agility and Strength actions become. Tier 1 armour might reduce damage by only d2, but wearers suffer no ill effects; Tier 3 armour might reduce damage by d6, but also reduce Agility by 2 and make attacks 2 points more difficult, for example.
Critical hits (natural 20) not only do double damage, but also reduce armour's effectiveness by one tier. Fumbles (natural 1) tend to lead to amusing disasters.
You get Reaction Rolls and Morale, as you'd expect.
PCs get a random number (commonly d2) of times per day that they can use something similar to D&D's Inspiration (though it tends to be called something like Devil's Luck or Glitches in the Borgs). You can use it to re-roll a dice (anyone's dice roll!), get max damage for an attack etc. No one ever remembers to use it. Fools.
There are often spells or spell-like abilities (Apps and nano-tech, in Hostile Space), but PCs tend to know one spell or have one scroll, if any, rather than having loads.
There are character classes, though you can make classless PCs too, though I never would. Each class has six different special skills: when you make the PC, you choose one or roll for one at random.
When you level up (pretty much when the GM thinks you should), you roll a new class skill (or strenghten one you already have).
Changes to your Ability scores when you level? Roll above your ability score (between -3 and +3) on a d6. If you can, add one to your ability score. If you can't, reduce your ability score by one (minimum -6; maximum +6. I think. Maybe? Maybe just -3 and +3? Can't remember)
More hit points too. That's it for levelling.
Oh, all the games have their own version of Mork Borg's Calamities: randomly-rolled disasters and signs of the coming apocalypse. Roll a dice to see if one occurs (you can choose which dice to roll, depending on how quickly you want the world to end. I don't even roll to see if one happens this day: I just have a calamity afflicted on the world when I remember to). Then roll d66 to see which awful situation happens: it is now in-game canon. I had one in my game of Ronin, when the PCs had just finished an adventure at the top of a mountain, that said that endless rain falls from the sky, flooding the lands. Horrible sea giants (ume bozu, I think) stalk the water-drowned realm. Fun. It very much set the agenda for the next adventure that we embarked on.
In Human Remains, because I wanted it to work for almost any kind of current-day apocalypse, I generated a bunch of different mini-catastrophe tables, to allow GM's to choose the ones that best fit their game-world.
If you can play one Borg, you can play them all. And there is no need for thousand-page rulebooks, unlike some other universal game systems. Short, stylish, and modular. Love 'em.
