Complex sentence: Inspired by Sega's "Virtua Cop", the game had originally been an on-rail shooter before the team decided to expand its scope and turn it into a free-roaming first-person shooter.
Split into simpler sentences: Inspired by Sega's "Virtua Cop", the game was originally set to be an on-rail shooter. However, the team decided to expand its scope and turn it into a free-roaming first-person shooter.