All About Love is the final mission of Metal Slug 3.
After dealing with various nonsensical scenarios, the heroes now deal with last batch of the Rebel Army who are about to launch various rockets in an open field. Not wanting to waste time, they ride on aerial Slugs and fly through the Rebel supply transport vehicles. There on the field is General Morden in his reformed Hi-Do, and the final fight begins.
Or did everyone on Earth thought it was. Turns out Morden was a Mars Person in disguise and was controlling the Rebels with the real Morden kidnapped and tied up to a Dai-Manji. The first player's character is kidnapped during the chaos, and the Regular Army and Rebel Army team up again to eliminate the Martians in space.
There are no alternate routes in this mission.
- Hangar: The players pick from a Slug Flyer and Slug Copter inside of two huts. If they take too long, the screen fades, and the next section starts with the players in their jetpacks.
- The Clouds: The mission starts with a dogfight against Rebel aircraft and parachuting Rebels. Defeat the various enemy waves to progress.
- Forest: Various cargo and tanks are seen driving by. Slug Copters show up whenever a player is in their jetpack. Allen O'Neil is fought here inside of a Hairbuster Riberts.
- Open Field: The final Rebel weapon base. "Morden" and his Hi-Do are fought here. A conveniently placed AA Machine Gun can be used to end the fight quicker.
- Space: The players use the Astro Slug to weave around UFOs and meteors. The Rugname (as in Metal Slug 2/X) is fought here.
- Rugname Hallway: The same thing as the previous section except inside a extremely long hallway. Occasionally, a large barrier has to be destroyed before it crushes the players. If the player is still riding the Astro Slug, then they'll crash on the ceiling and has to dismount it at the next section.
- Rugname Entrance: The proper on-foot section starts here. The section is accessed by breaking open a barrier protected by Mars People. Hyakutaro can be found here.
- Electric Prison Cell: The real Morden's holding place guarded by Elite Mars People. Break the computer to save him.
- Rugname Center: A hallway full of relentless Hopper Mechas. The exit door lowers down by shooting at it.
- Fake Rootmars: A incarnation of the Martian leader in a secluded room. Destroying it causes the Rugname to self-destruct.
- Organic Hallway: An orange hallway covered in organic flesh. Clones of the captured character jump from the right. The SV-001 is found and used in this section. If the Slug is destroyed/not ridden, then Allen O'Neil miraculously shows up to help the heroes.
- Clone Incubator: The captured character is held inside of a stasis container that produces these clones. Break it to access the next section.
- Exit Hallway: The final stretch closed off by multiple doors each with three locks. Zombified clones continuously attack from the left; use the protrusions to dodge the zombie clone's vomit lasers. The LV Armor is found here. The end of this hallway are two SV-001s for the players to ride in while the captured character attempts to open the hatch. Once it opens, everything falls down back to Earth.
- Clouds Again: Looks like the Martian leader, Rootmars, is also falling towards Earth and has grabbed the SV-001s. The true final fight takes place in free-fall.
There are 16 POWs in this mission, but they don't appear until the players enter the Rugname. Aside from a single prisoner, all of them are hidden.
- Due to its multiple lengthy auto-scrolling sections prior reaching the proper on-foot portion, this is the longest mission in the Metal Slug series.
- How the hatch opens in the final section depends on the captured character. Marco and Fio opens the hatch without problem. However, Tarma and Eri kicks the computer in frustration, and the hatch opens.