I bought this game on my Switch because it had great reviews and I'm a sucker for NES era games ... but I'm just not feeling this for whatever reason. I mean it's ok, but the gameplay to me hasn't seemed particularily ... great so far. And it doesn't quite have the same charm as NES games do. It feels like going to that kid's house who didn't have a NES in the 80s/early 90s but had his dad's work PC which had like a weird approximation of an NES game, lol. 

Is it worth giving this game another shot? I've gotten good playtime out of Fast RMX and NBA Playgrounds, but this one just isn't clicking with me. Am I alone on this?

Depends on how far you're in it.

I beat the first boss or whatever and am now into the second world. I get that they're trying to be a bit like Megaman meets Castlevania or whatever, but I'm not feeling the game in terms of its charm either. Levels are way too long and level design isn't great IMO. 

Game was meh to me as well. I beat the first few stages and just stopped. I just could not get into it.

Same, I have around 10 hours play time before stopping. Worst 25€ I've spent on my Switch

It never got good for me, Shovel Knight from beginning to end felt like a nostalgia cash-in where all you do is hold down to win, so yeah...

It gets good the second you start it.

It stays like that. You get more abilities and items, and of course each stage is different from one another, but what you've seen so far is largely what that game is all about.

Specter of Torment is way better.

If you love NES games, get your hands on Blaster Master Zero. Great game!