Based on the Chinese novel “Journey to the West,” SonSon and its PC Engine only sequel SonSon II are side scrolling platformers with RPG elements where you kill monsters to acquire zenny (money) and use that zenny to acquire the items you need to complete your quest. You don’t “level up” as such but if you’ve played games like Wonder Boy III (Wonder Boy and the Dragon’s Curse) you should be well familiar with the play style.
The amount of Japanese in the game is minimal and won’t impede your progression if you’re not fluent, and it’s one of the more affordable PC Engine titles in the library if you want a physical copy. Give it a try! Subscribe to Mistah MegaManFan (mmf187) for new content every night at 8 PM ET including The PC Engine Files every Tuesday.