Keith Courage, Alien Crush, then I am pretty Sure Bonk's Adventure.  #4 was R-Type.  It was all pretty early on in the system's lifespan, I got Bonk when it came out.  I remember picking up R-type as a new game in our local flea market (Well, one of my parents did, I was a kid at the time.)  Keith and Alien Crush were Xmas presents along with the TG-16.  I still have to replace AC while it's still considered "common!"