Here is my theory,
Alien Hominid and Battle Block Theater are in the same time cause at the end, Alien Hominid crashes his spaceship after he beats the Beefy Alien.
Then, since the Beefy Alien was in Castle Crashers, that means Castle Crashers in in there with them. Then Game 4 is right after those 3.
After look at other posts, it could be that Castle Crashers is AFTER Game 4 and the Beefy Alien might be a mutant alien. Which explains the crazy stuff.
Alien Hominid+Battle Block Theater -> Game 4 -> Castle Crashers!
The Castle Crashers dude in BBT is probably from the future. (best guess)