OH cool! You can use ships you don't have in time attack. You can do this by selecting the ship you want to use and there you go :) Quite good if you want to test some ships.
Note to self. Never play this game if I have exceeded my bandwidth limit cause after waiting for so long for the game to load and clicked the play button it gave me... a white screen D:
 "Enigmata"){kind=icon}
 "Bloons Tower Defense 3"){kind=icon}
 "Little Wheel"){kind=icon}
 "Age of War"){kind=icon}
 "Electricman2HS"){kind=icon}
 "Bunni: How we first met"){kind=icon}
 "Super Crazy Guitar Maniac Deluxe 3"){kind=icon}
 "The Great Siege"){kind=icon}
 "Neverending Light"){kind=icon}
 "Music Catch"){kind=icon}
 "Dungeon Defender"){kind=icon}
 "Omega Tower Defense 2"){kind=icon}