Unsurprisingly, UFO 50 seems to have a big secret meta game that I've only just scratched the surface of

pcgamer.com:

UFO 50 has taken over my life these past few days. When I'm not glued on the simple Windjammers-esque pleasures of Bushido Ball, I'm throwing my great big walrus body around perfect blue skies in Waldorf's Journey. I don't think I'll be able to ever stop playing it. In her review Kerry called it a "superb retro-style smorgasbord".

In addition to hosting 50 8-bit style console games belonging to a fictional 1980s studio, UFO 50 is really dedicated to the fiction of its games' provenance: each has a precise little history, and running through the whole collection are references to other games in the collection. It also has a terminal accessible in the main menu which allows players to enter eight figure codes.

[Word of warning: If you'd prefer to discover all this yourself, be aware that potentially huge spoilers follow.]

Well, players are discovering codes at a rapid rate, both on the Steam community forums and Reddit. Some are merely functional: the prefix EXEC- followed by the relevant four-figure game code will load that game. For example, EXEC-GOLF loads Golfaria. Similarly, the prefix HELP- will bring up a list of commands for the game. You can access GOLF's placement in the full list of games with the LIST-GOLF. If I enter LIST-GOLF, I see this:

Note that it only shows 17 entries at a time. If I enter the last game in that list with LIST-OVER, I see all the way up to 50. But what if I try to see beyond 50? Well, there's apparently a 51st game with the codename MIAS. 

This isn't the only way to discover the 51st game by the way. One Reddit user found the code in Barbuta, which is the first game in the UFO 50 menu and, if you don't mind me saying so, a huge glorious pain in my arse. There's also this Reddit thread with a bizarrely elaborate chain of events leading up to the discovery of EXEC-MIAS and beyond that I haven't followed myself, though suffice to say, there are other related codes that aren't just shortcuts. 

What is the 51st UFO 50 game? Well, it