#mm4

.𝒎𝒆𝒍𝒂𝒏𝒊𝒆 𝒎𝒂𝒓𝒕𝒊𝒏𝒆𝒛 𝒽𝒶𝒹ℯ𝓈

Hmmm. My own biased opinions:

#50: Buy it. It's controversial, but it's fundamentally important for the series as a whole — the entire transition from the main series to the endgame hinges on this one. It's got excellent (heartbreaking) moments between Cassie and Michelle, Collette being awesome, and good ethical discussions.

#53: Buy it. In some ways this is more of a finale for the series than #54 is, because it explains how the war ends and depicts ~90% of that ending. #54 is firmly a post-war book; this one is the actual resolution to the overarching plots of the series.

MM4: Take it or leave it. There are tons of great character moments, but it's an AU adventure set in a timeline where the Animorphs never became Animorphs, and doesn't ultimately have anything to do with the main series.

Hork-Bajir Chronicles: Take it or leave it. I can hear the enraged howls of fellow fandalites even as I type this, but since you specifically mentioned wanting something lighter, this does not fit the bill. It's extremely well-written, but it's also narrated primarily by a settler colonist who turns on colonialism too late to stop her people from committing genocide.

#44: Leave it. There are 2 or 3 great moments of Cassie being badass, but like MM4 it's a weird one-off that has nothing to do with the main story. And unlike MM4, it doesn't give us any big character reveals — Cassie's moments of badassery mostly echo stuff from #29 and #34.

Alternamorphs: Save your money. As @lucario2012 and @derinthescarletpescatarian have pointed out, they're not even structured correctly — you can't follow story paths unless you guess correctly every time, there aren't clues within-story that can guide you to make the right choices, the choices don't occur frequently enough, and none of it creates a sense of agency. It seems like Scholastic hired a ghost to jump on the "choose-your-own-adventure" trend, gave them 0 training in game theory, and this mess of dying over and over again was the result.