Owlboy is kind, but it is also long, and a lot of its difficulty comes from the camera and the companion system rather than from enemy damage.
Throwing the carried companion stuns enemies and is the fastest way through a swarm. It also reaches switches and ledges that a shot cannot. Press R to recall a dropped companion rather than walking back to them.
Different gunners handle different enemies. Bring the one whose damage type matches, and when a room resists gunfire, bring Twig with his sword rather than grinding shots into an armoured target. Lava Lizards in particular waste every shot you put into the head.
Poison jar plus water equals toxic sludge, which petrifies enemies and opens carnivorous plants. If you are stuck on a puzzle involving a plant or a wall, you are probably two steps short of making sludge rather than missing a key.
Ride a cloud, rain on it, and throw it into a suction vent. Cork a vent and a cloud may need to go somewhere else entirely. Reading the sky as interactive rather than decorative is the single biggest shift in how you solve Owlboy rooms.
Blind gnomes are harmless in the dark, but flesh-eating bugs attack you for being in it. The two enemy types pull in opposite directions, so light is a tool rather than a default setting - and a light source you carry into the wrong room is an invitation.
Turtle: kick the shell off, then it flies. Temple Guardian: petrifies under a waterfall, so use water. Giant Gawk: it is a mob with a health bar. Monkey King: seven enemies, one arena. Lava Worm: ride it once you win. Sky pirates: only one attacks at a time. Fighting each boss as a damage race when it has a specific solution is the most common first-time mistake.
There is no fast travel in the base game, so the efficient method is to pick a region and clear every room in it rather than bouncing between regions. Tokens, Ish items, companions and secret areas are all in the rooms you walk past, not behind the story gates.
Screen-shake and flashing-light toggles, cutscene skipping and auto-aim are all in the anniversary update, and all of them make the game better for almost everyone. Auto-aim in particular lets you play with one thumbstick or entirely on keyboard, which was the main complaint about the original controls.