The reason we always give that response is because we know nothing about you.
We don't know what consoles you own, if you own a PC/how good it is, what types of games you like, your preferred length, do you like glitches or RNG, ect.
We can recommend you all the games in the world (which will just be games we like and run) but you could either hate them, doesn't fit your length requirement/opinion of what a good run is, ect.
For the purpose of this question, I'll answer this: Undertale, Deltarune, VVVVVV, and Ib-all are short ish games, the longest being an hour, with glitches throughout the game but with glitchless categories, and they're all PC games that can run well on most PCs.
I could say Warframe, because it's free-to-play and has a variety of different categories to play around with. But this could also be an #Ad.
Your best bet is to find the games you like to play and just try to speedrun those games. I've personally tried multiple games, including games I love and games I hate, and I am still not interested in many of them to speedrun. You'll be able to speedrun a game once you are personally motivated to speedrun the game.
You just proved my point.
If you’re going to ask this, can you at least provide some information about yourself? Like what consoles you own, what games you own, your budget, preferred length, what types of games you like...
We can’t help you if we know nothing about you. We’ll just keep recommending games we run.
I would try any of the games you've already done.
or try this sick ass game https://www.speedrun.com/randomgame
With all due respect, it’s not our job to research you and your runs to try and guess your interests. Most people here don’t have a desire to help someone who doesn’t explicitly state what types of games they’re looking for because it goes a lot like this thread already has.
“Try game x, y or z” “No I don’t like those” “Try game a, b, or c” “No I don’t like those”
We’re not just gonna sit here all day and keep posting games if you don’t do anything to help us, nobody has time for that. Also, having looked at your profile, it looks like you’ve run games in a few different genres so it’s not much to go on (also, just because you ran a game like Fallout doesn’t mean you like RPGs, maybe it was a one time run and you didn’t like it).
Additionally, if you don’t like a lot of games then this is a weird hobby for you in my opinion. Part of this hobby is liking the games you’re running because if you don’t, you’ll get frustrated, bored and burnt out easily. All of that removes the fun from something like this. It’s why that’s always the go to recommendation, because we don’t want people to get annoyed trying to run games they don’t enjoy playing.
We’ll be glad to offer our help, but you need to help us as well. If you have a decent PC, your options are quite numerous since you can run tons of older games through emulator instead of just running native PC games.
You might be interested in the Resident Evil and Destiny series as speedruns. I'm not too familiar with the games as runs, but Resident Evil throughout most of the games has quite a few glitches and Destiny has some elements of FPS. And like you said yourself, Portal and Amnesia are also fantastic speedruns themselves. Hope that helps.