Awesome! This kind of gritty lo-fi ambience is totally my jam, and I like how you keep the tracks really varied and non-repetitive but at the same time each of them has a distinct quality/personality to it. They fit their descriptions well. I'd love to play a game with this soundtrack!
Also, kudos for using "default" instruments. I feel that often that kind of decision cuts down the time wasted looking for just the "right" sound, and lets you focus more on composition and being creative instead. Also the resulting sound is more cohesive as a result.