Roguelikes with the potential for broken builds.
Sometimes you find the perfect combo on your run and become an unstoppable force, but it doesn’t ruin the game because you finish your god-like run and next run you try to find another overpowered build.

I’ve very rarely disliked “prepping”. For example building boss arenas in Terraria or setting up my equipment for a hunt in Monster Hunter or learning about the monsters in Witcher 3. Anything that lets me prepare for future encounters is a system I enjoy, even if it’s only superficial.

I hate it only when it’s turned into somekind of a survival element that exists solely for the purpose of resource management. For example I hated hunger and water in Subnautica. From a certain point forward those two things become just mindless busywork because when you plant it in your base it just grows and whenever you need to fill up you just go to your base and eat and drink and there’s no upside nor a real downside to those two mechanics.

Puzzles, traditional or unique, as well as physics and spatial-heavy thinking.

Parry and riposte mechanics make me happy. Idk why exactly, but something about timing a parry and making the enemy entirely helpless for the followup is just great.

Broadly speaking, I enjoy stealth in games as long as it’s implemented correctly and doesn’t break the game or function poorly and leave you at a disadvantage. Despite the many qualms I have with tlou2, the added mechanic of going prone and all the upgrades associated with stealth was quite fun—and, of course, the functionality of the bow and arrow, and how you can conserve ammo. Parsing an area with dogs and navigating their heightened scent through long grass and deciding when to pick off certain enemies or ninja though is tremendously fun for me.

Desperados III and Shadow Tactics are two other stealth games that I love that use a design similar to The Commandos series. You can navigate through their detailed environments deciphering a path through on your own, using whichever abilities your party has to your advantage. I think the ninja/feudal Japan game world fits better with Shadow Tactics (I also prefer the characters) but Desperados III has just as good, if not better level design.

To add a somewhat weird one, I’ll say a good save feature. Saving with an ink ribbon in RE was so freaking awesome—especially in regards to how it adds a level of complexity to item management. Another cool example that doesn’t add anything to gameplay but was neat: ICO and how you save your game with Yorda on the couch. So wholesome; I can hear the music in my head, even.

More floaty, less realistic platforming. Thugs like double jump, or somehow your character has less gravity when they jump, stuff like that. Stuff like that. As a general platformer lover, I really enjoy more fictional cannot be done IRL physics in games.

Among plenty of the other things mentioned, I enjoy “diagetic interfaces”. Ways of interacting with a game’s systems that stay grounded in the reality of the setting of the world. Dead Space is a prime example, but I’ve been enjoying a lot of the crafting in Vintage Story for this reason. The smithing in particular has had me hooked for a while. Hammering out my armor and weapons voxel by voxel made finally suiting up and feeling ready to take on a boss that much more satisfying.

I’m a sucker for crafting and breeding systems that allow you to customise equipment and/or characters. But it’s really hard to find good implementations of the idea, most have some obvious flaw:

• Pokémon (breeding) - in early games RNG plays too much of a role, so it’s hard to get what you want. Late games don’t fix this, instead they allow you to skip the process altogether (see: hyper training).
• Niche - the breeding part of the game is actually really good, a shame that the rest of the game is a slop. For example gathering food gets a PITA once you got too many nichelings, and yet you want them to support your breeding pairs.
• RimWorld (Biotech; germline genes) - arbitrary restrictions that must be lifted through the usage of mods.
• RimWorld (crafting) - now we’re talking. If you pay close attention to which materials you’re using for which tasks, it pays off in the long run. There’s some luck involved, but you can get perfect (legendary) stuff fairly often if you know what you’re doing.
• Leaf Blower Revolution (leaf crafting) - the game encourages you to craft a lot of leaves and salvage most of them. That’s fine, it’s easy to get cheese anyway. The problem is the sheer amount of beer that you need to get the properties that you want in each leaf.
• Monster Breeder (old Flash game) - the game is a bugfest, and the lack of any sorting system makes you have a hard time even knowing which monster you should be breeding with which.
• Minecraft (tools and weapons) - vanilla has a really dumb system that doesn’t fit well in a game that encourages hoarding piles of materials into chests. The mod Tinkers’ Construct fixes this, and makes the system next to ideal.

Plus a lot more that I didn’t mention. Sorry for the wall of text.

I like most game mechanics to some extent. Creativity in combining game mechanics is key to making an outstanding game imo.

However, I don’t like things that force a time limit. I play games as an escape. I don’t like feeling stressed by a clock while I’m off the clock. These can be literal timed missions or things like a food/water meter. Escort missions also suck for similar reasons.

I think difficulty in a game should come from overcoming a foe, traversing harsh terrain, or solving a puzzle. If the game is hard because I have to stop what I’m doing to feed myself, or I have to rush to complete an objective on a timer, it just becomes work.

Peaceful exploration

I love fluid movement. Doing things in a state machine is usually the way to go in 2d platformers, which is what I mainly make. I like when your character can move around without issue, so double jump, sliding, rolling, attacking etc.

I’ve only realized it recently that I’m obsessed with simulator games. Eurot Truck Simulator 2, Software Inc, Minecraft? Rollercoaster Tycoon, etc.

Save anywhere

I love the histogram system from Zachtronics’ games. I find it much more useful to see my score compared to the proportion of people who got a similar score, than a leaderboard rank that doesn’t mean much.

I really like Zelda and Ys style ARPGs. Specifically, rare and impactful loot, and little reliance on skill levels, but rather skill aquisition. Both approach it very differently, and later Ys games fall into more traditional RPG mechanics (e.g. farm money/exp, buy gear, etc), so I’m more talking about Ys 1, 2, and Origin, as well as pre-BOTW Zelda games.

Basically, I love this gameplay loop:

1. Enter dungeon/level and fight baddies
2. Find important item/ability
3. Use important item/ability to defeat monsters
4. Fight boss, using a mix of important item and learning movesets
5. Repeat 1-4 several times, with plot mixed in
6. Fight final boss using a mix of everything acquired

Ys and Zelda do this in very different ways, and I absolutely love the level cap in Ys 1 to enforce playing smarter instead of grinding. You can never really get OP, even if you try (except Ys 2, which I don’t like much).

Unfortunately, “ARPG” has been twisted to mean Diablo-like, which is heavy on loot and ability trees instead of puzzles and exploration, and future Ys games go that direction as well.

This isn’t really specific to mechanics or systems, but I’ll like pretty much any mechanic or system that lends itself well to that gameplay loop.