Over the past 15 years, Metroid Construction has hosted over 20 contests (aka "jams" or compos"") and produced over 100 hacks for them in total. One of the admins claimed that the latest contest was the best contest in the history of the site, so (lacking any official data) I decided to trawl the archives on the forums to compile some basic stats from every past contest.
From the data, we can conclude that the 2024 Star Base Contest was indeed the largest contest in the site's history, and in terms of the number of high-quality, high-effort entries only the oatsngoats contest can compare. (Congrats to everyone, I guess.)
This chart also reveals some other trends, such as how Zero Mission hacks started to appear in contests once the game got a good editor, while the other games in the series (M1, M2, and Fusion) tend to only get sporadic amounts of entries regardless of the quality of the tooling.
Anyhow, I put the master list of contests and contest hacks on my website, if you're curious to take a gander: