While Space Quest 6 is a tad buggy and doesn't particularly follow in the excellent vein of the other Space Quests (probably due to a lack of Rob Lowe), Space Quest 4 and 5 are by far the best Space Quest games available. 4's dark storyline and quirky humour are absolutely fantastic together, while 5's hilarious premise and exceptional characters make it my personal favourite of all the Space Quests. The ability to fly your own spaceship and to play Battlecruiser make this game a ridiculously fun adventure. Also I personally find 5's storyline the peak of the Space Quest humour without a doubt.