Marvel's Secret Invasionwritten by Brian Michael Bendis with art by Leinil Yuwas, was Marvel's big 2008-2009 event. Bendis had started teasing the event in the pages of New Avengers from the beginning of the series before really ramping things up in 2007. Bendis revealed that the Skrulls had been planning the invasion for years and when their plans were revealed, it was already almost too late.

RELATED: 5 Ways The Ultimates Has Aged Well (& 5 Ways It Hasn't)

Secret Invasion is a well remembered event by fans. It's slow burn build-up was one of the best Marvel had ever done. Like anything, though, not everything about the series stands up.

10 Aged Well: The Art

Leinil Yu got his start on Wolverine back in the mid-'90s and has pretty much spent his entire career at Marvel. He's drawn just about every big character the publisher has and that ability served him well on Secret Invasion, which involved the heroes of Earth fighting a desperate battle against Skrull invaders.

He did an especially good job with the superpowered Skrull soldiers. These soldiers would incorporate iconography of the hero whose powers they were copying into their uniforms, which doesn't make a lot of sense but looked really cool.

9 Didn't Age Well: "He Loves You."

"He loves you," was a creepy thing that Skrulls were saying to people they took out in the first issue of the book, like when a group of them ambushed Dum Dum Dugan or Hank Pym revealed himself as a Skrull and took down Reed Richards. Fans thought that it would go somewhere interesting and were psyched to see where.

However, the reveal was lackluster, at best- the Skrulls were referring to their Skrull god. This god didn't show up to tackle the Avengers or anything. It was just a creepy thing they said that didn't really matter in the long run.

8 Aged Well: The Ad Campaign

Skrull Embrace Change ad showing two human children smiling and laughing with one skrull child

Between this and Civil War, Marvel was killing it with the ad campaigns. Before the series started, they had artist Greg Horn draw a variety of Avengers, X-Men, and other Marvel heroes as Skrulls, with the tag line, "Who do you trust?". Later, there were pictures of Skrulls doing regular human things with the tag line, "Embrace change.".

The campaign got readers hyped for the story and played up the fact that any hero could be a Skrull, while the later ads played into the series itself, as the Skrulls were telling everyone that they were just going to destroy the heroes and try lead normal lives and fit in with humanity.

7 Didn't Age Well: The Action Scenes

Bendis wasn't well known for writing action packed stories and his events were no different. Secret Invasion isn't as bad as House Of M, which mostly eschewed action scenes for people yelling about how much they wanted to kill Magneto, but the action scenes in it are uninspired to see the least.

RELATED: 5 Ways Infinity Gauntlet Aged Well (& 5 Ways It Hasn't)

They're mostly just pages of giant confrontations between the heroes and the Skrulls that rarely focused on any particular part of the fight. It's especially egregious because Leinil Yu is one of the best action pencilers in the business and Bendis give him very little to work with.

6 Aged Well: Reunited

Post-Civil War, the Marvel Universe was a fractured mess. There were two teams of Avengers fighting each other, Captain America was dead, and the X-Men were busy trying to keep their race from being exterminated. The Skrulls revealed themselves at the perfect time, taking advantage of the divisions between the heroes.

As Secret Invasion  went on, the heroes would team back up, leading to the moment when Thor, Iron Man, and Captain America (well, Bucky Cap, but still) lead the heroes into battle as Nick Fury quipped about his god having a hammer. It was a great moment that still stands up.

5 Didn't Age Well: The Lack Of Highly Placed Skrulls

For a series that promised all kinds of big reveals of heroes who had been masquerading as Skrulls, there were surprisingly few big heroes revealed as such. It was pretty much just Hank Pym and Spider-Woman, with no other Avengers, X-Men, or Fantastic Four members and there's something that is just so disappointing about that.

For months, Marvel had been pounding fans with ads and stories designed to make them question who among their favorite heroes was a Skrull and when it was revealed that just about no one important was a Skrull, it made the great ad campaign and stories look a little dumb.

4 Aged Well: The Skrull Queen Reveal

A Skrull impersonating Spider-Woman in Marvel Comics

Spider-Woman was revealed to be Veranke, the Skrull Queen, and it was a great reveal. The character had been going through something of a renaissance at the time- she was a member of the Avengers, always involved in the big kerfuffles, and taking a prominent place in the Marvel Universe.

RELATED: X-Men: 5 Ways The Dark Phoenix Saga Aged Well (& 5 Ways It Did Not)

While there were very few other reveals of Skrull imposters, this one almost made up for the lack of them. Fans were shocked that she was the one behind everything and it still plays well all these years later.

3 Didn't Age Well: How The Skrulls Were Able To Copy The Heroes' Powers

While Skrulls could change into just about anything or anyone, the one thing they couldn't do is copy the superpowers of those they were impersonating without heavy experimentation. So, fans were shocked to see superpowered Skrulls with Marvel teasing a big secret behind why they were able to do so.

The reveal was... that the Skrulls pretty much just did what they always had done but they had also gotten their hands on some of Reed Richards's research as well. All things considered, it was a pretty lame reveal.

2 Aged Well: The Ending

The ending of Secret Invasion was a totally out of left field one and it set the stage for a very different Marvel than fans were used to. Instead of one of the heroes getting the kill on Veranke, Norman Osborn got it as television cameras were rolling. This changed everything.

Iron Man's lax leadership was blamed for the Skrull takeover of S.H.I.E.L.D. and kicked out with Osborn being put in charge. He would gather his own shadowy Cabal of villains and a new team of Avengers- the Dark Avengers.

1 Didn't Age Well: The Pacing

Secret Invasion (2008)

The biggest problem with Secret Invasion is the pacing. The first few issues of the book were very, very slow, with just about nothing of any actual import to the story actually happening. The two teams of Avengers were trapped down in the Savage Land for about four or five issues and things moved at a glacial crawl.

The last few issues, by contrast, moved way too fast and it made the whole series feel a bit disjointed. The beginning is so slow and kind of boring and then end is too fast, with bad action (but great art), and it all feels very disjointed.

NEXT: 5 Ways Secret Wars Aged Well (& 5 Ways It Hasn't)