Travel through time, defeat aliens, grab golden orbs, save history...stuff like that. Unfortunately, you don't get to do all this courtesy of a blue box - it's not that kind of a game.
Unused Weapon Icons#
What appears to be a flamethrower weapon that would be best suited for the final stage.
An alternate/early version of the pistol, which may have gone better with Stage 3. The weapon is also found in Stage 5, but in both cases a different icon is used.