"Sailor Moon Dating Simulator 4" is the fourth game in the SMDS series, centered around Rei Hino (one of main characters in the "Bishoujo Senshi Sailor Moon" anime series). The goal of the game is to win love of Rei Hino by asking her out on dates, giving gifts and playing mini-games with her. You have 15 days with one possible date (or other action) per day. Answers selected during dialogues on dates will eventually affect Rei's feelings (i.e., "correct" answers will raise "intimacy level" and "wrong" answers will reduce it).
You can go shopping for gifts any time during the game. Once you have a gift, you can give it to Rei during any date. Day 16 is the last one, the ending depends on your actions. The game has four possible endings. If you get the best ending you'll receive a love letter from Rei (instead of a regular letter which means you failed to win her love) asking you for a date.