Kingdom: New Lands

One of the older games still left on my backlog this time. (Fun fact, there's apparently also a Flash version, not that those are easily accessible anymore as of this year.) I've had my eye on Kingdom: Classic (which kind of acts like a free demo these days) since it came out in 2015. But before I got to play it, Kingdom: New Lands was already out, so I opted for that instead. I seemed to have missed Kingdom: Two Crowns for some reason, which came out in late 2018.
So, I only played New Lands, but from what I read, the core gameplay is basically the same for all of them. Each next installation just adds a bit more content. So keep in mind that what I say probably applies to all of them.

Kingdom is an extremely minimalist strategy game. You play as a ruler, who gallops left and right on their steed, and the only thing they can do aside from this movement is to collect money and choose where to allocate this money. You can hire workers, get them tools to build/hunt/farm, fund farms, defenses, and some other stuff like shrines. After a few days, you'll be sieged by monsters each night. Survive long enough to build a big boat, and you win.

To start from the good bits - I find this minimalistic gameplay quite well executed. It's intuitive, and you can really do quite much with effectively only one interaction button. The art is really nice, and the music is fitting and beautiful.
Now, as for the problems - they mainly come down to pacing, unit AI, and general lack of content. The map is pretty long horizontally, and your movement isn't that fast. You have no overview of what is going on outside of your immediate view, so you're going to have to move around a lot, spending most of the game just getting from one place to another. It's slow, and it's not fun.
Secondly, the AI is really not up to par with a game this hands-off. If I can not micromanage my units, they must be capable of managing themselves. These fools will happily wander outside at night, getting beaten up by monsters and losing all my hard earned money. Builders prioritising important or nearby buildings? More like random things, sometimes even aborting an ongoing project to go elsewhere. And archers just... don't know where to go. They have no idea where to find enemies or animals to hunt. All in all, it makes for a frustrating experience, seeing such incompetence unfold.
Other problems are just the lack of building, unit, and enemy types, as well as sometimes lacking clarity of what some things do.

To conclude, Kingdom isn't a bad game or a bad idea, but it needs better AI, and a faster way to get around. Most of all though, it needs more content. In that regard, I would have almost certainly been better off trying the newest version, and you definitely should skip straight to that if you want to play Kingdom, but I understand it's still not a significant improvement. As such, I would have to give the overall series a "no". There's probably plenty of strategy games out there that would rather suit your fancy. This one doesn't respect your time, and even if you invest in it, you'll never reach satisfying gameplay. A bearable way to pass the time, at best.

Wolf & Rabbit

The thing with RPG Maker adventure games is that they're either going to be really good, or a waste of time. Wolf & Rabbit seems to fall more into the latter category.

There isn't much to say about adventure games in general. As they don't tend to be gameplay-based, the "game" is not a point of discussion. The story, however, obviously can't be talked about without spoiling it, leaving little to say. Wolf & Rabbit is about 2-3 hours long, depending on how stuck you get.
Maybe I'm just dumb, but I feel the game is very non-straightforward, forcing you to backtrack and re-search a lot of places you've been to before, because those places inexplicably gain new items you "did not see before".
The game kills you for stupid reasons, forcing you to go to the last save point and through the dialogue boxes with forced wait time that can't be skipped, being a major annoyance.
And the grand finish is that this game is translated from Chinese by someone who's not exactly an expert in English, making it a painful read most of the time.

In the end, I was probably mostly through the game, but the story didn't grip me enough to even care to see it through to the end. It's supposed to be a horror game, and does have some slightly eerie moments, but nothing truly scary either. The writing isn't very good, even if you don't account for the bad translation, and... what's left, really? The nice art and melodies playing in the background? Not enough for me to give it a recommendation. There's better adventure games out there, horror or not, RPG Maker or otherwise.

Ruiner

Ruiner is an action shooter / hack-and-slash. It's got some story and takes about 6-ish hours to complete. You run around some levels, whack enemies with your melee weapon, or pick up some guns to shoot at them, while using some abilities to help.
Truth be told, I didn't get very far in the game as I was immediately put off by one glaring flaw. The game is in this top-down, almost isometric view, and you control your character with the WASD keys. But... pressing down actually moves you down and slightly to the left. Likewise, all other directional controls are slightly angled. In a game where precision and fast action taking is important, this movement scheme is unacceptable. I can not play a game when the character is not moving where I am telling them to move. This in and of itself is more than enough to not recommend this game, but wait, there's more.

Honestly, the game just feels a bit boring, and has some unnecessary elements. It presents a variety of guns, but with their limited ammo, the mobility of your character, and the damage of your trusty handheld pipe, there's just no reason to not go up to everyone and whack them instead. Likewise, from the selection of abilities, not all are equally useful. The game's too short, repetitive, and running around dodging and whacking people is a snoozefest, so I just really see no reason to recommend it.

Trackmania

Already been quite a while since I first tried the "2020" Trackmania. One of the earlier Trackmania games actually stands as one of the first "real" video games I played (not an indie Flash game or Minesweeper or sth.), so this series has always had a special place in my heart. Not that I'd ever been a particularly active player, but I feel it's at least something I can always return to.

Trackmania is a simple game. It's a racing game, which tend to be simple in and of themselves, but Trackmania eliminates any possible lingering complexity surrounding the driving. Everybody gets the same car, no upgrades, no abilities, no interaction with other people aside from seeing their incorporeal cars race alongside you. You only have your gas, your brakes, and your steering, and this allows you to focus on the important bit - driving.
You see, Trackmania is probably the only speedrunning game I have enjoyed so far, and that's because it makes it so accessible. Completing a level and getting a Bronze time is easy. A Silver might take a few tries. But as you approach a Gold (or the extra hard "Author time"), you really have to start embracing the speedrunning mindset, where a single mistake like bumping a wall or braking at the wrong time ruins the run and warrants an instant restart. On some maps, that's where the difficulty comes from, on others, you also have to watch how you take curves, manage your speed, etc. They're not difficult concepts, but everything has to be executed near perfectly and refined over dozens of runs.
While usually speedrunning would have you go look up tricks from the community, here you can always fetch some replays from the game's servers of people who are just a bit better than you, showing you areas you could improve in. So while it's possible to be stuck for a while as you struggle on the perfect execution, you will never have a problem that you don't know where you can improve.
All that's not to mention any user-created tracks, which often go crazy with jumps, loops, wall-driving, and other shenanigans.

I still have mixed feelings about some new track elements they put into the game. I enjoy the new ground types, which have more variety than older games, like the drift-oriented gravel, or slippery snow. However, I have not yet come to terms with ice tracks, which basically rob you of your steering ability. Nor do I like the track effect which literally robs you of your steering ability until the next checkpoint, and the "reactor boost up/down" effects are unintuitive as well. I think these elements increase the skill floor needed to enjoy the game, and that's not something I wish for this game, even if it's not a problem for the seasoned player.

Overall, while I'm not super excited about Trackmania, I do see myself playing it from time to time, completing a few tracks, seeing my leaderboard ranking increse and medals rack up. I would definitely recommend trying it, since it's the first and only racing and speedrunning game I care about, and I feel it's got to be special to do that. It's also free, so nothing lost if you don't like it.