My version tips was a bit more geared for contests/jams since this is a jam that I'm posting this for, but you definitely made it more clear for how to do it properly beyond contests.
(Note, the 'you's I use below here are generic and not directed at anyone in particular).
So some further emphasis on things that I think are especially important:
Testing is a very important thing that usually gets skipped or gets a lot less attention than it really needs. People like me who usually become more aware of bugs over time instead of less aware are rare (though things like time and hardware still limit my ability to test. That and bugs are only one aspect of testing). You can call people like me exceptions, really. For most people, you need a variety of testers that can test various problems. You might have your primary testers that will do the preliminary testing, but once they are done, you might want to hire a new tester because someone coming in with a fresh perspective might be able to see bugs that someone too familiar with the product might miss. Beyond just testing for bugs though, you also want people that can test for issues unrelated to bugs. Balance, pacing, and other elements of UX are all important to test for. One thing I highly recommend is that whenever you think you have a stable build, have someone test from the start to the end. A lot of companies rely on level specific testing. This is fine for most things, but sometimes a bug can occur because of something that happens between stages/levels. Maybe the item you picked up from 10 hours ago ends up triggering an event it isn't supposed to in a later stage, for example.
And yes, testing your changes and any possible side effects your changes might have is extremely important. If you don't have time to do a full test, at least do that much!
Yes, project management is extremely important, especially as a project grows. Good project management can really make or break a game project, especially when deadlines are involved! Time management is, in some senses, a small part of project management. I focused on time because a lot of people seem to have issues with that, but project management is very important. Definitely saw a lot of projects where project management could have made a huge difference to the resulting project.
One tip I have related to project management for jams is to set two goals: One goal is your minimum level. Plan your project to meet that level. This is going to be based on what you are almost certain you can do. Next is your expansion goal. If you have remaining time, what do you want to do? Now, Look at what is common between both versions and these are what you want to work on first, if possible. For example, if battles aren't necessary for you to finish your game (fighters and arcade shooters are examples of when you need battles), you might want a complicated battle system, but are willing to settle for a less complicated system if necessary for time reasons. In that case, you might want to not work on the battle system until later (so you don't have to redo balancing later on). Then, once you've reached the point where you have to work on your battle system to continue, you can look at how much time you have left and set your goals for the battle system there.
This sort of management can be especially important if you are still learning the engine. As you work on your game, you might understand the engine better and this can make the harder parts of the project easier. Think of it like you might want to learn how to kneed clay before you make a bowl. You might want to make a ceramic bowl before you make a ceramic ocarina. Building off easier steps makes it easier for most people to do harder steps. Exceptions apply, but don't plan on being an exception unless you already know you are one. Even if you are an exception, you still might want to start off with the easier tasks because it is motivating to get more stuff done.
Believe it or not, motivation, morale, and rest are extremely important and are things that I believe should be a vital part of project management.
To go further on attacking your critics, not only will you potentially anger reviewers, let's players, critics, etc., but you might also end up with a bad reputation from other developers, publishers, and even players. It can go further than that as well, so definitely never attack your critics.
This is really more a rule than a guideline. Let me put it this way, I know people who won't buy certain things because the creator was shown to be very disrespectful/discriminatory to certain groups of people. You also don't want to later on end up not hired because you pissed off some recruiter's brother and that brother told the recruiter all about the incident. Or just as bad, your supervisor goes on youtube and sees you blasting off personal attacks on someone. Even if unlikely, don't think it can't be traced back to you just because you don't use your real name. These are all possible outcomes that are just not worth it over a comment you don't like and caused you to lose your cool.
Also, be aware that a simple difference in perspective can anger someone. Like, I tend to say phrases like 'you want', 'you don't want', 'you should', and 'you need', but there are people that will grow angry with such word choice. For those people, I have to be extra careful that say "I recommend'. Even if I mean the same thing with both word choices, the other party might not see it that way. Even a casual phrase like, "You are beautiful", can be considered sexual harassment (people have lost their jobs due to saying someone was beautiful. One woman adamantly demanded a guy to be fired for basically saying she looked nice).
Basically, this advice goes beyond just reviews, but in interactions with others in general.