Hi, I was surfing today and saw your post. On the IPDB, I hesitate to appear definitive on game "firsts" when so many older games have not yet been "seen" or "discovered". In the case of drop targets, most folks today are understandably only familiar with the type of target that your game has, first seen in Williams 1963 "Vagabond" So, I'll make a note in that listing to direct people to earlier versions of this target. In this way, sometimes there is no specific "write-up" on a feature, but you have to go exploring. Two way to explore on the IPDB is to use the Advanced Search to search for "drop.target" in the Notable Features box (minus the quotes, but include the period between words to lock it in as a phrase) and also see what we have to say in the Glossary for that term.

Drop targets have been seen as early as 1936.

Thank you.