Complex sentence: Another early concept which was scrapped was that sniper mode would only be available to the player during the boss fight at the end of each level, but this was changed so the player could use sniper mode whenever they wished.
Split into simpler sentences: Another early concept which was scrapped was that sniper mode would only be available to the player during the boss fight at the end of each level. This was changed so the player could use sniper mode whenever they wished.