I'm 100% sure that you skipped on reading the description which explains the R thing. Also that you played for maybe a minute at max and probably closed before even attempting a high score/ shooting once cause if you did play it to give actual feedback like others you would see the global leaderboard in the beginning & the end of the game. Again about no clear instructions - only if you read the description.
I could add a backstory to the game but doesn't really make sense to do so when I choose to focus on making my game function & work properly as opposed to adding a 2 minute backstory in description for the sake of 'storyline'.
Nevertheless, Thank you for your feedback.