The point of Porygon-Z being "overpowered" was simply to reference the glitchy nature of Gen 1. Porygon-Z being based on a virus program was the perfectly way to illustrate. PoryZ is also not strong enough to 1 shot every Pokémon while being prone to getting revenge killed since it's relatively frail.
It's also a Pokémon you get super late and you're only able to obtain a single Dubious Disc before the E4, so it doesn't consume the whole playthrough. Porygon2 is also not nearly as insane if you still want to use a Porygon.
You get it after badge 5 so most of the game, esp. the climax, is post OP pory... Also mewtwo doesn't oneshot everything but is OP af in vanilla...
Played through again, my rules were no legendaries, no sleep on my side, no items except pokeflute in battle, no porygon.
My critique (not nuzlocking):
1) It is - if we ignore porygon, as said with porygon it's total ass - definitely the best gen 1 hack I've played since you feel rewarded to have a somewhat balanced team.
2) It is a little bit on the easy side. For example if I got extremly unlucky in later gym fights I still had multiple mons left after the fight, I didn't change my teams based on the gym. IMO (just MY opinion) one should die at gyms if one gets very unlucky (if one didn't change the team for the gym).
3) Porygon way too OP, prolly better than mewtwo in vanilla
4) lvl curve is good except right after victory road - was the first time I used rare candies, I used 2 to get to lvl 60 from 58 pre elite 4. (very minor, maybe I missed something)
5) sleep is broken and would need some fix... I personally would love a "hard" mode (still easy) with a lower level cap for elite 4, no items in battle, sleep fixed somehow (maybe (npc and player) can only sleep 1 mon or just sleep totally removed or something...) and maybe banned for the player (or severely nerfed), no porygon, harder trainers, etc...
6) I don't think there is a need to lower thunder wave accuracy, it seems like damage is the way to go in this mod anyways. I had to reset once in the elite 4 since my only twave user magnezone missed... (Had to reset at lance a few times as well for team comp and lvl reasons.)
7) gym fights were too easy in the second half of the game, random trainer fights were almost always very easy (maybe supposed to be like this?)
8) documentation is great!
9) overall balance changes, items added, route changes feel great!
10) there is no end game, after elite4 the game ends - which is fine, i tried the battle tower for a short while, seems like it's made for porygon, not sure if you can bring 2 porygons, if you can the play is probably to bring 2 and bring one special attacker who deals with the beefy guys (basically in the early levels you get through by just pressing A with porygon which usually kills 2-3 mons lol, just swap if enemy has high defense or prolly use ice beam? got too bored to try, also no docs on enemies so you'd have to go through the whole tedious thing again which is boring even on 5x speed, since well, you spam A with pory for 60 or so levels... worst experience ever)
Here is my team after completing the game. alakazam, scizor and gengar were the best, crobat performed great, magnezone and blastoise were decent but not close to alakazam, scizor or gengar. team was build to fill the hole around alakazam (mostly used him). used mankey then hitmonlee pre scizor and butterfree pre gengar. barely used blastoise or his pre evolutions. at level 64 (I rematched the elite 4) scizor + alakazam solo the rival. (for a more easy time on level 58 or 60 one should replace magnezone, blastoise and crobat with probably things like aerodactyl?, some ice type? and so on, problem on low level is that your fast mons are slower than the slow mons of the npcs. if you level up to the cap this is no challenge, can prolly bring anything which isn't too onesided.)