That is impressive. That's a lot of work to hide your activities from other people, though. Sufficiently paranoid? I say yes. But then again, I have not met many impressive hackers in real life.
How much reading up did you have to do to figure each of those things out? Or was it trial by fire? Figuring out all that on your own?
More the other way around, that I'd read about how to do such things and then saw an opportunity to put them to use.
I had been self-teaching assembly for a couple years from library books and doing other toy programs. One book, possibly one of Peter Norton's, covered the partition table in sufficient detail. (And I was hacking only one byte in it, nothing sophisticated.) Reading and writing a disk sector in assembly was commonly covered in reference books. So was writing a TSR to hook the timer interrupt, which I'd already done for some other purposes. The actual logic of looping through segment B800 looking for text wasn't hard in assembly. Overwriting and masquerading as a legit program (VSAFE) isn't a technical challenge at all. The hacker chops were thinking my way through the detection methods and countermeasures, more so than the actual programming.
If I hadn't had that background, I would probably have hidden the games with less sophisticated methods. Bury them in deep subdirectories, maybe zip them with password encryption. And it was done for the challenge more than the results; I had a home computer that could play all the same games.
Anyway, I'll relate another story.
There was an annoying kid in my computer science classes, the type who thought he knew it all but was pretty clueless. One day he was complaining that a game he had downloaded required more RAM than his home computer had. I told him I'd give him a copy of a utility that would do on-the-fly compression of RAM in DOS. (At the time, Stacker was big for disk compression, and there were real utilities that did memory compression in Windows. So it was plausible.)
Of course, my "utility" was a trojan. But I was subtle about it. The trojan dropped an executable with a blank name (an Alt-255 character) and stuck a reference to it in AUTOEXEC.BAT, which was invisible and looked like a blank line. The payload would trash the partition table, only if the system date was a month later than I originally did this, so he wouldn't be tracing the time bomb back to me. (Yeah, this was nasty. I was a youth with power.) I don't know if he actually ran it or if the payload ever went off; the bomb date was in the summer after school ended.
But the real fun part is the postscript. The outer trojan was in QuickBasic (the dropped payload was assembly.) Years later, my brother was playing with QuickBasic to learn it, so I gave him a copy of my QB directory with several dozen of my programs to play with. A few days later he tells me that his computer won't boot. Yikes. I put together a boot floppy with a Norton disk repair utility to start digging, and eventually notice that the partition table had some corruption that looked oddly familiar. You guessed it, my own brother had run my old nasty trojan and got his partition table nuked!
Reminded me of coding a funny practical joke TSR program which after several days showed a message 'Press and hold left Ctrl + left Alt + W + Right Shift + P + M to see a surprise!'. After victim would press this combo, message changes: 'Now, when you release these keys I'll format a floppy inserted in your drive A:\' (that was the time not everyone had hdd on C:\ yet;). The picture of someone sitting with their hands stuck to the keyboard and shouting for help was just too funny.. however, testing the payload, time after time to ensure everything would be working as prescribed, the first victim was I myself, stupidly forgetting to remove diskette from the drive after another run. The sources were on A:\. Nobody home. Mother comes back from work in about 3 hours. Damn. I tried to open the hatch on the floppy drive door with my leg fingers to prevent diskette from being erased. Then quickly jumped to pull it out, though the drive has made a number of cycles before it was escaped.. and the source lost forever:) that was already enough fun not to bother about it again;)
Both the idea ("hold these keys"), and how it ended up backfiring.
Though the program would have given just as funny results if you had not actually formatted the disk on key-release. After all, how is the user going to know whether the program speaks the truth?
How much reading up did you have to do to figure each of those things out? Or was it trial by fire? Figuring out all that on your own?
Seriously, kudos. Those are some hacker chops.