Just for fun, let's make up hypothetical game design decisions that are so bad that no developer would ever implement them. (Alternatively, if a game has actually implemented any of these, perhaps that could be mentioned.)

For example:

* Game seems to have a normal save system, but when the game crashes, it intentionally deletes all your saves. (Note that this does not happen on game over; so not typical permadeath.)

You don't want to give them ideas now do you?

How about these?

You can play the game for X hours and then it locks itself and you have to pay to unlock it.
Whenever Windows 10 updates, you have to reinstall the game ayyy lmao
You have to carry 20 studded leather armors to buy one healing potion oh wait
The game is locked Monday-Friday 9-5 because you should be working.
Game is locked to 30fps:P
You can only play on 720p until you pay for the extended imperial deluxe edition of the year

and last but not least

You have to watch ads in the game, oh boy should I delete that before a developer sees it?

Game has no DRM, but the installer is still bundled with a client, enabled by default.

This is going to be a short list... :-) Aside from "intentionally" there's been a few AAA titles in the past that did pretty much the same thing with borked / game-breaking buggy save-games in games using a single-slot checkpoint-only save system, forcing a restart.

But you are probably so tech savvy that you can untick that box even you were blind ;).Cheers

Need for Speed Rivals actually is You're too late, Ubisoft have already done this for Rayman Adventures I have that feeling too...

Whenever you save and load your game, the manna cost of your spells goes up. Oh wait, this is a still existing bug in Heroes of Might and Magic 6.

When uninstalling a game it deletes your entire hard drive... wait, that actually happened.

::looks warily at Pools of Radiance Ruins of Myth Drannor cds::

Hey hey, calm down! Do not go giving them ideas!

- The more you use a spell, the weaker it becomes. At some random point your spellcaster becomes irreversibly transformed into a frog, who then is picked up by a stork for dinner.
- At every levelup of a character, there's a random chance the character loses all levels in his class and has to start at level 1 in a different class.

Didn't pool of radiance, second version, remove system files on uninstall, so not far off that! Still a good game if you get the patch and play solo.

* Create a forum thread called "Evil things game developers could do, but don't" to harvest evil ideas that they couldn't think of themselves.

If you use cheat codes, the enemy later gets to randomly use cheat codes against you.

An adventure game with the length of The Longest Journey, the dead ends of Space Quest 4 and King's Quest 5 and the save system of Uru. Have fun >;).

Banjo and Kazooie did it one better. Using cheat codes too many times caused the game to erase your save data. No problem, you say? The situation is completely irreversible on that cartridge forever.