I recently finished Space Rangers. I purchased the Space Rangers pack during the Summer sale.
It's a very addictive game and I enjoyed it. However, the difficulty is unforgiving, even on the 'Normal' skill setting. It was very frustrating at first and I started over about 5 or 6 times because I couldn't make any progress.
Doing the missions early is imperative. I acquired a faster engine as soon as I could to outrun pirates and finish the missions on time. Some of the missions are clever logic puzzles which I thought were fun.
One of the mistakes I made during my initial attempts was failing to collect protoplasm for the ranger stations. You have to do this to upgrade your skills.
By the time the end of the game was nearing, I had all the best equipment available with upgrades. It wasn't hard for me to clear out systems at that point and I easily defeated the Klissan boss.