Dinky Dungeons rules ported to space! And expanded quite a bit. Unlike Dinky Dungeons, which is very simple, in Small Space, you have Physical skill Points (PP) and Mental Points (MP) equal to your Physical and Mental scores, respectively. You can then buy certain skills with those PP and MP - some skills require one or more MP, some require one or more PP, some require both, some require either. There are no skill levels - you either have a skill or you don't - not having it means you have a penalty on the Idea or Muscle roll - or in some cases, can't even try the skill at all. Small Space only has nine skills to choose from, so is not that much more complex than Dinky Dungeons so far.
But it goes well beyond that. Other expanded rules include: Space ship generation and combat rules, futuristic weapons, invention rules, alien races, planet generation, initiative rules, etc. --user description