In the first mission of Battlezone, it’s possible to travel out of the map and find a 1960s lunar lander that you can enter and pilot. It’s equipped with a one of a kind super weapon that plays trance music as you fire it.
Unfortunately it’s only available in the first mission and you can’t take it with you to subsequent missions.
100% this has been my last two years in gaming. Xcom, Warcraft I and II, Outpost 2, Stars!, Cave Story, Sim Tower/Sim City, Darklight Conflict and now working through Chrono Trigger