but it would require the save file/cookie used for these IGM games to not be overwritten whenever you play a different game if possible.
the idea being, a series of games where you could only proceed to the next after finishing the previous one. like say... going through all of the mega man (classic series) games in order > mega man x games > zero > ZX as one long continuous game. just one after the other as one really REALLY long game split into pieces.
just have something at the end of each game toggle a flag or something in the save game that'd allow you to start the next in line. this is what would require the file or cookie or whatever is used to not be overwritten.
and even with how simple this IGM format is, my mind just goes blank when i look at the text file. :/ sadly, i'm more likely to just have ideas than actually make use of them myself.