A bit off-topic, but i'd be skeptical if size of modern game is only 1.55MB.
Maybe it can be, if the exe is only a launcher and the actual game is somewhere else or it's in dlls.
That would make sense if we're talking about legit game. But why would people who crack game bother create launcher program? They could use BitTorrent protocol or cloud storage (such as Google Drive) to share cracked game easily.
I'm not sure I've got your question right.
A legit app may have a launcher, especially if it's expected to get (many) updates. Seen that, not in games though (I don't play lately, so I don't know).
The crack is probably a downloader. This way some AV may not flag it, since it may have not much of malicious code, but the downloaded package is probably a "bomb" for the OS.
Of course, in the case the legit exe is a launcher, probably a "legit crack" (lol) would have been replacing some dlls, not the exe.