So it's meant to show the game and its mechanics and usually it's not expected to test the player skills (at least I don't recall any demo that I play in quite a few years that is not fairly easy).
Your demo should be representative of what the final product is like. If players are meant to take away that your game is "easy, thoughtless, spam attack" then show that in the demo.
If you game is meant to have thoughtful skill strategy, show that.
Dark Souls isn't going to have a demo when you have infinite stamina and 1 shot every enemy & boss. It's going to have a demo that shows the game has punishing difficulty.
And maybe this is being pedantic but you should clarify the terminology.
Demos usually are bite sized chunks of a finished game for the player to try before buying.
Beta tests are usually early access to the development build to receive feedback. (and more accurately, likely "alpha" would be the correct term, but we're adding pedantry on top of pedantry, so let's leave it at that)
In the RM community, I've come to expect most people to just call their early access games "Demos", but it can lead to an impression that what people are playing is mostly finished, ergo no placeholder stuff.
If it's necessary, and I advise doing so: Add a message at the start of the game reminding folks: A) This is a development build, and B ) all of the current things to expect and not expect, such as placeholder assets or balance changes and missing content.
Concerning the tutorial, if it is not meant to be frontloaded as you have done so currently, I would highly suggest informing players of that (again, just a little message box, "due to this being an early build, I will crash-course you on the important tutorial information" then remind them how to access that information again in the future, "please go to x menu to read this information again in case you forget it."
The main point is: Just make sure you are communicating with your player what it is exactly they are playing.
Best of luck. I may check this out in the future.
p.s.
Speaking of pedants, No idea what @RCXGaming and @Cythera are smoking. Outside of RM, most