==UNLOCKABLES==

-Art Gallery-
This will tell you which games are needed to beat to unlock an art gallery.
+---------------+---------------------------+
| Unlockable    | How to Unlock             |
+---------------+---------------------------+
| Art Gallery 1 | Beat Metal Slug           |
| Art Gallery 2 | Beat Metal Slug 2         |
| Art Gallery 3 | Beat Metal Slug X         |
| Art Gallery 4 | Beat Metal Slug 3         |
| Art Gallery 5 | Beat Metal Slug 4         |
| Art Gallery 6 | Beat Metal Slug 5         |
| Art Gallery 7 | Beat Metal Slug 6         |
| Special Art   | Beat all Metal Slug games |
+---------------+---------------------------+