13% off - that's barely saving anything at all, and it's not the cheapest game and it doesn't even include any goodies except the manual :(

As someone who doesn't own a physical copy I have no idea what goodies were included with the original game. But if a lack of goodies is one of your main complaints, you should consider telling GOG's product team (via the support) what your ideas for additional goodies would be. I'm sure their artist could whip up at least some high resolution wallpapers or some papercraft dolls.
At least a try wouldn't hurt.

I'm including the full resolution avatar of GOG user matsufi as an example - I think it looks cool. :)

Not that I care too much about it the goodies, it's more that I find the game to be somewhat overpriced and the "discount" only adding insult to injury. A nice set of goodies might have helped mitigate the issue somewhat, but the game doesn't even have that, making the price even more aggravating.

The way it is now, I'll probably just end up never playing the game, since it doesn't hold any nostalgic value for me, and even though I've heard good things and am curious about it, I can't see myself buying it with a less than 50% discount, when there are other games available.

That's understandable. I think the current pricing is mainly aimed at customers with said nostalgia.
From what I gather Jazz Jackrabbit was incredibly hard to come by legally before it finally came to GOG. If you look at the wishlist entries for Jazz Jackrabbit you'll see that several thousand users expressed their demand - similar to the Captain Claw situation, but with more votes. I guess part of GOG's deal with Epic Games was that they would go through with a release on GOG as long as the price wouldn't drop as drastically. I think the situation is at the very least an improvement over the time before the GOG release, where people had to pay collector prices in order to get a copy.
Personally, I agree that the current pricing doesn't offer much of an incentive, but I'm glad that thousands of people on GOG were able to finally enjoy the game.

I think it's still far better than the Interplay approach of raising the base price and claiming their games got cheaper by offering a higher discount percentage-wise...

That's it, yeah. This is the first time since 2012 it's been possible to buy Jazz 1, and the first time since 2000 it's been possible to buy Jazz 2. It doesn't make a lot of sense to immediately discount everything.

It's because these games aren't very long on Gog, I remember the X-wing and Tie Fighter games also took a couple of years for the price to drop before I considered (re)buying them.
In the end just vote with your wallet, if you think the price is too high just don't buy.

As far as I know from watching LGR, so it was indeed. The reviews on the channel are also the reason why I wanted to play the games, but my personal hype train for them got somewhat derailed by the prices. I mean, just because the game was rare before digital release existed, doesn't justify the digital copy being expensive. Digital-only copy is not exactly what you'd call a collector's item.

Hopefully, there will be a proper sale one day. After all, there's only so many nostalgic people, and discounts are going to have to happen in order to attract new players to the games. I sure know I can wait until that happens.

But anyway, enough with the salt. What really matters is

Honestly? If they were to include every version of Jazz Jackrabbit 1 ever released with this instead of just the final version, it'd probably be well worth the $10, partially because some later versions of the game broke some things in earlier levels by mistake, and partially because version 1.1 is about as elusive as a version of a game can possibly get, to the point that some people I've talked to in the Jazz Jackrabbit community didn't believe it really ever existed in any capacity until I pointed out that the shareware 1.1 definitely existed, since it's still possible (albeit really hard) to hunt down the download for. (It still remains a mystery whether or not the full version of 1.1 actually ever existed on that note, so having that confirmed officially would be kinda neat in of itself.)

Well, that and maybe include some MP3s of the soundtrack or something... just sayin', but the soudntrack is kinda worth a few bucks by itself.

...not that it's very hard to open up the soundtrack in OpenMPT and export the songs as MP3s yourself if the shareware version is anything to go by, but it'd be nice to have an easy, convenient way to be able to listen to the soundtrack on just about everything without manually exporting them. Speaking of which, it'd be pretty easy for GOG to slap together such a thing for both the first and second Jazz Jackrabbit games themselves if they wanted to.

(Also, for the record, the original Jazz Jackrabbit's manual had a comic in it from my understanding, so it's a bit more than it sounds like it'd be. I don't know if they still include it with the GOG release's manual, mind you, but just thought I'd note that while I'm typing all this other stuff.)

For some perspective: When the original registered version of this game was released in 1994, it cost USD$39. That’s the equivalent of USD$65 today. So GoG asking USD$10 for it today isn’t that bad ;)