Sometimes games that belong to the same genre achieve different levels of success among the playerbase of the genre. As an example, of two space RTS games Homeworld (released in 1999) and O.R.B. (releasedin 2002), which feature a similar setting and similar gameplay mechanics, Homeworld has beenmore successful. The purpose of this paper is to investigate the reasons for the different popularityof the two games, using game reviews as the primary source of data to learn about the strengths andthe weaknesses of the two games. Thematic analysis has been applied to a total of 27 game reviewsof space RTS games Homeworld and O.R.B. Codes describing various strong and weak aspects of bothgames have been extracted from the texts. The codes have been grouped into various categories traditionallydescribed in game reviews, such as the story line, the UI, the graphics, etc. Using these codesas a basis, a number of explanations have been suggested as to why the game Homeworld has beenmore successful than the game O.R.B. The main reasons discovered are that Homeworld was releasedseveral years before its competitor and that some of important game features of O.R.B. suffered frompoorer technical execution in comparison to equivalent features in Homeworld.