I just beat Owlboy. Don't waste your money on it.
The pixel art isn't the highest tier, but it's up there. Sadly, it's the games only redeeming quality.
The music is well made, but not memorable. I beat it just minutes ago and can't hum a single tune from this game.
The story is mediocre. It's a typical "we am play gods" storyline that never bothers to fully explain itself. At one point you fight a boss simply because they "don't have time" and "don't want to" explain themselves. After you beat them, they explain themselves, and of course you had no reason to fight in the first place.
The game itself is the worst. I think that on the usual 10 point scale that game reviewers use it would get a 5 or 6, but on a real 10 point scale where 1 is some truly unplayable garbage, this is a 3 or 4. There are so many extremely significant and fundamental flaws in this game that it often makes you want to throw your controller like the old days.
The screen scrolling is often severely fucked up. There are many situations where it scrolls to a new screen like in the old days before Mario invented smooth scrolling. Even if it does scroll smoothly, your character is often on the very edge, so you can't actually see what is coming at you. It doesn't move the camera appropriately so that you can see enemies or the next platform you have to jump to. On top of that, it gives you very small margins of error for actually dealing with those things. You have to play many sections repeatedly and memorize them to survive as a result. Imagine if the arrows in DDR appeared at the top of the screen instead of coming up from the bottom. That's what this game does.
Also The controls aren't unusable, but have a bunch of flaws that add up to a major annoyance. The worst is the web-grab hook shot thing. It will lock on to all sorts of unnecessary things. Also, it works no matter where you shoot it, even on just walls. They provide special points for it to hook to, but it hooks anywhere. Then they put you in situations where you need to use it very rapidly, and it doesn't work.
The firing button is the right analog trigger. This is fine except holding it down doesn't rapid fire at maximum. So you end up pushing the trigger up and down rapidly and hurting yourself. It's not an analog control, so it should have been on a face button.
The shotgun reload is very very slow. Too slow. The shotgun has another mode where it just puts out a little bit of fire. If the reload is done, it will fire at full blast no matter what. If it is not reloaded, it will shoot the little fire no matter what. if it's full there is no way to use the little fire. There are situations where you just want to use the little fire to burn something and keep the gun loaded. You can't do that.
Many levels have major design flaws. There is no map. It's not always clear where to go. Often you will be backtracking, with nowhere new to go, but you're not sure if that's right. There are many buttons you press without any clear function. It's also not clear which buttons require a character too stay on them, and which are permanent.
The game constantly takes control away from the player to have characters talk with text for extended periods of time. It also will frequently put you into situations where you have limited or restricted movement, and is very very slow. Look at the best games of all time such as Super Metroid and Half-Life 2. The player is in full control of the character nearly 100% of the time. Even if you are trapped in a room while something happens, you can jump and shoot and run at full speed. There's a reason for that. Owlboy gets this so so wrong.
And then, on more than one occasion, the game throws you into immediate action with no chance to ready yourself. The boss will finish introducing themselves and them immediately start shooting before you can even move yet. Notice how in Mega Man the boss does a little dance and their energy meter fills up? There's a reason for that. Have the people who made Owlboy even played games, or did they spend their entire lives drawing pixel art?
The animations of getting hit are really bad. Some animations make you think you got hit or took damage, and it's not clear if you actually did or not. So you'll end up maybe not doing a move that is actually totally safe because it looks like you took damage the last time you did it.
When you do actually get hit, you often get slammed like a knockdown in Street Fighter. That is not appropriate for a platforming action game! This is not a fighting game. You lose all control for seconds at a time. Your character gets moved to who knows where. And then you stand up with bad guys still moving and doing shit to you. Results in a lot of one-hit kills despite having plenty of health remaining.
The core mechanic of the game is that you have to carry your friends around and they actually do stuff. You do the flying, they do the shooting. Changing friends is changing weapons. You have a magic teleporter to switch them as easily as you switch weapons in Doom. This core idea isn't bad.
The implementation is bad. First off, the hitbox is only the owl. Your friend can get hit by anything, no problem. This isn't always clear. There are many times where I dodged unnecessarily because it looks like I'm going to get hit. I actually ended up making myself get hit.
Also, the button for picking up or dropping a friend is the same button for picking something up off the ground. If you are carrying a friend and want to pull something out of the ground, what do you do? You drop them. Oh, you dropped them in front of the thing on the ground. Now you can't get the thing on the ground because your friend is in the way. Now you have to pick up the friend and throw them somewhere else. There is no button to just make your friend disappear.
Owlboy is really really short. I beat it in 5 hours, many of which were spent repeating bullshit sections. It wasn't worth even the Steam sale price, and not because I think time = game value. It's because this kind of game needs to be longer to be good. The story suffers the most from the short length.
For example, early in the game a town is destroyed. This works in say, a Final Fantasy game. You walk around the town. You meet the people. You start to care about them. You learn the buildings. Then they destroy it. Owlboy you walk into the town and now it's blown up. You never meet a single inhabitant. How can I care that it got blowed up then? I don't care. I don't care about anything in this stupid owl universe, and I really like owls.
TL;DR: Unless you want to pay a lot to look at fancy pixel art, save your money. Not even worth $5. Wait for $2.50. Current Steam price is $20. No good.