Lets break down what you get with each
If you give Zack flying counters, trample counters, or other keyword counters, those can also be passed on to another creature
1 Secret Lair Drop Series: Marvel Superdrop Heroes Don't Quit Captain America, First Avenger Iron Man, Titan of Innovation Wolverine, Best There Is Storm, Force of Nature Black Panther, Wakandan King The first of a huge crossover Universes Beyond with Marvel Comics, the Secret Lair Drop Series: Marvel Superdrop saw five different drops release, each one based on a different Marvel hero
I also added the mana pool emptying to it, based on @Zaga's
Doctor Doom survives the bounce his Doombots and Plans are your permanents, which stay in play
If you have too many attackers or your attackers have evasive abilities like flying or trample a single creature with deathtouch wont save your opponent from taking damage