Planet 28 is a narrative skirmish game using dice and miniatures. Death on the Periphery (DotP) adds a simple solo/co-operative mode to the game. Essentially, this boils down to rules for a warband to have a single character, an optional table of agendas for co-op play (which are great! I really like the Pacifist one), a tweak to spice up activation for the non-player artificial intelligence (AI), and a very simple AI for the baddies. The AI basically uses as many opportunities as possible to attack the player's warband, with no variation for different mindsets (cautious, methodical, etc). Having said that, the warband creation rules in the main rulebook includes traits such as coward, so you can just create your enemy as you wish them to act. The supplement ends with a short campaign of three linked encounters, with full stats for two different enemy types. The campaign is designed to be played solo or co-op and it looks like it would be a great intro to the game.
For a competetive or co-op game I think the crunch is probably just right. I do worry that there's a bit too much dice rolling crunch for solo play though. I've found that I only want small warbands to cut down on the amount of dice rolling.
Death on the Periphery adds even more tools to the toolbox that is Planet 28. I think that you can do pretty much what you want with this game and it's dead simple to hack. The vague setting is implied to be murder hobos in space I think, but the rules allow for fantasy, pulp, modern, ancient, etc with a minimum of hacking.