User blog comment:Spike144/History of towers and their upgrades/@comment-4275518-20120309184241/@comment-4795804-20120310110049

You can see an "evolution" of BTD series in the table. If you're familiar with the towers and upgrades in BTD5 and want to play some older BTD, so you can see which towers and upgrades you can expect. Anyway, this page is mainly for fun, that is why I didn't create it as an article but only as a blog.