So having nearly completed and explored just about everything in this game, I have yet to encounter any bugs, but some of the gameplay is so insanely frustrating and arbitrarily senseless that I have wanted to punch my laptop.
BUTTON MASH QUICK TIME EVENTS
These things in your game are an abomination, they don't serve to better the gameplay or increase the challenge, they make the game ANNOYING, FRUSTRATING AND NOT FUN! I nearly stopped playing when I hit the Alien Probe event, and again at Randy's Abortion, it's ridiculous
Alien Probe: pretty much can't be beaten with a keyboard, unless you want to damage it.
Randy's Abortion: the dilation part is again impossible to beat with a 360 controller without damaging it, and the suction part needs a better indicator. The needle part does not respond correctly to your button presses sometimes, just to screw you over.
Goth Dance: obnoxious, has to be done nearly perfectly to get it to work, I've missed like, three or four presses and that caused it to fail, again, better indicators needed.
Boss Fight Quicktimes: Kenny's summons are not the worst but really annoying when you have slow reaction time and aren't expecting it, theres no real warning.
For the love of god make a checkpoint happen right before farting on kenny's balls or at least refill the player's mana.
I deleted my save in frustration because after that whole long-winded boss fight I had no mana, used a potion and ended up overloading on it and letting cartman die, causing me to have to replay THE ENTIRE FIGHT. ugh.
Saving needs to happen on-the-spot recording everything that's happened instead of just shunting you back to the last checkpoint and clearing all your progress, again, obnoxious and arbitrary and a poor way to use saves in an RPG
Burn and Bleed might need to be toned down a bit, they're kind of insanely powerful
Stun, Sleep, Gross Out and Pissed Off on the contrary are useless at the end of the game because nearly everything is immune to them. Maybe give these statuses alternate effects on immune enemies or take away some immunities, because they become pretty much worthless by the time Nazi Zombies become a thing.
Jimmy is just awful, there's almost no reason to use him, he does no damage and only boosts your PP, which you can do with a potion, and if you have the perk you can get the Attack Up his buff would have given you for using said potion. Also the potion doesn't take up a turn. Make Jimmy;'s quest give him the Flute as a weapon that deals AoE damage to everything and inflicts a debuff, that would really help, also giving him some form of healing, give him HP/PP regen buff as his special ability instead of PP boosting, this would make him really good
Stan's final ability is awful, just awful, his spin does more damage, to more enemies, please fix.
Kenny is kind of bad all around. he's hilarious, but pretty boring and sort of an "everyone does his job better" character. I still feel like he should transform into Mysterion sort of like butters does.
Enemies have a large number of issues:
1. They're dumb, and can't prioritize targets and don't really use strategy
2. They don't even use the same mechanics as the players, they can't block, counterattack, or use free items
3. They don't have a very wide range of abilities, except bosses, and the ones they do have are generally solved with a cure potion
4. Strange, sometimes arbitrary values of XP for defeating them, I've gotten 5 XP for killing 4 elves and 20 XP for killing 2 elves, both at level 4.
5. They can't change positions at all, might not be a bad feature to implement in DLC.
6. Late game most enemies are just obnoxiously hard to kill with really high armor, there's not much variance, no squishy super high damage mages or super beefy heal tanks or back rank snipers, just lots of nazi zombies.
The leveled class-specific gear you get for completing portions of the main storyline is generally completely useless by the time you get it.
Also some gear is just flat out broken, like the SWAT Helmet, which can allow you to pretty much win every non-boss fight without ever giving your enemies a turn, just drink a cheapo 2$ speed pot, AoE damage/debuff effect first hit either a spell or a bomb/bouncy weapon weapon Bleed/Burn on it, then go to town with the Katana (also stupid broken) one dude after another.
Also the weapon system doesn't make a whole lot of sense, once you get the Katana basically every other melee weapon is a worse choice. You really need to split the balance better:
Statistically superior weapons and armor with no strap-on/patch slots
Weapons and armor with unique effects and 2-4 strap-on slots but really low/no overall stats
Some stuff that fits somewhere in the middle of those two
And WHERE ARE MAH SET BONUSES? you guys went to the trouble to include all these armor sets, but no full set bonuses? WHAS UP WIT DAT?
Some perks are basically mandatory like the one that gives you Attack Up every time you use a potion, or the +20% to HP, others are totally useless and serve no purpose at all, like most of the fart perks, might want to do some tweaking.
Moar Perks is never a bad idea either.
What the heck is up with the mana mechanic? I never seem to have ANY mana at all because it apparently doesn't come back after fights or even regen over time and I can't fill it up because I'd just crap myself, needs some work.
I might suggest that instead of mana potions, all potions increase mana very slightly, and mana regens over time in the game, and you can use toilets to lower mana, and you get one turn to use your overloaded mana before crapping yourself except against Jimmy's Brown Note.
OVERALL COMBAT BALANCE
The basic mechanics need some work, because nerfing/buffing other aspects of combat could make things worse or better, take things as a whle and just try to make combat more interesting, make mechanics flow together better.
Now that I'm done, I just wanted to take the time to say thank you for making such an awesome game, and I hope you can make it even better.