(I didn't have time to write a short answer so I wrote you a long one, SORRY FOR WORDINESS)
Back when I made a strip that was primarily a funny comic, it was because I had ideas that I thought were funny, and I fiddled with the timing and the wording until it sounded as funny to me as the idea had been in my head. Sometimes I'd post something where the joke didn't quite land because I just couldn't get it right, and other times I'd be giggling at my own jokes for weeks afterwards, but the guiding light was always to try to tell a story that made me laugh!
Overall I don't feel like your stuff is tiresome or unfunny as it stands! It's subdued, but it's also just getting going; it's mostly goofy commentary on what's going on, and playing most of the suggestions straight.
For the kind of thing you're doing, the natural source of humour when you don't have a lot of elements in the story is playing off the suggestions -- e.g., for a suggestion to not do what people expected, teasing an obvious suggestion and then misinterpreting it every possible way, having a completely ridiculous suggestion somehow Work Out Perfectly in an unexpected way, etc etc. If you want to look to other examples, the most obvious comparison is Jailbreak Adventure, which gets a lot of its (weird, occasionally gross) humour from making every suggestion go horribly wrong in an unexpected, over-the-top way.
Obviously, being very sadistic isn't the, uh, only option, but I think playing with the expectations of a suggestion could be a good direction to think in.
It's like improv, right? Everyone gives that advice in doing improv of trying to respond with "Yes, and" --- you want to agree with the scene your partner sets, and then add something of your own to it.
So like, in improv acting, if Person 1 starts a scene saying "Good morning, everyone, welcome to space camp," and Person 2 just says "Yup, we're your space camp instructors," that's, fine, but it means Person 1 has to reach for a new idea since Person 2 didn't take it anywhere. If Person 2 responds instead with, "What, no, this isn't space camp," then that just shoots down the scene. BUT, if Person 2 responds, "YEAAAAHHH, definitely space camp, where you'll definitely go into space and you shouldn't ask any questions about our credentials please we are definitely astronauts," that builds off what Person 1 started but adds something new to it, so that it's easier to make new jokes!
So to apply that idea to you, if someone says "pull the chain out of the wall and make a skull flail," and you respond, "okay, I made a skull flail," that's fine! But it means the askers, your improv partners, now need to think of new ideas. If you say "I am definitely not strong enough to pull the chain out of the wall," that's okay to do, but it makes that suggestion a dead end. If you say, "I pulled the chain out of the wall and now part of the wall has crumbled?!?!? also how do I attach the chain to the skull." -- that kind of thing gives your askers something new to react to! And if you play off the suggestions in a really unexpected way with timing or wording that makes you smile, there's a good chance it'll entertain your readers, too.
I think it would be a mistake to give Every Single Question that kind of "Yes, and--" answer. But it might be another direction to think in when you're trying to think of an entertaining place to take your readers' suggestions!