pretty solid, cute little platformer. I wrote my review before reading through the game page and realizing that you built this in your own engine, so I'm guessing your focus is more on engine dev than game dev, and I think thats cool. great job on being able to make a solid game in your own engine that runs well.
as far as the game goes, I've got a couple tips that would probably be pretty easy to add that would go a long way in juicing up the game.
- when you die, the level instantly restarts, this is known to be pretty disorienting to players, especially in instant kill platformers like these. Adding even like a short death animation that hangs and gives some feedback would go a long way. I would also recommend not restarting the level but having checkpoints and resetting only the player. if the lights continued after a death it would allow the player to get more information about the challenge they died on which will motivate them to try again and learn instead of getting frustrated. of course, keeping the restart button in case they end up in an unwinnable situation and need to truly reset the level
- the jump feels extremely floaty. i would try and tighten the velocity curve such that the player ascends very fast but also quickly loses speed and falls back down. you could also make it so they fall slower until they release the jump button, then start falling down faster after releasing. I would recommend watching this video and paying attention to the breakdown on some of the fundamental movement mechanics in a few well known platformers
https://www.youtube.com/watch?v=yorTG9at90g - since this game is about an owl flying through night, maybe you could lean into the animal aspects of the owl character, like a hover / glide ability by pressing and holding space in midair? might give the player some extra tools to help them out with the tougher jump levels like 7 and 8
keep up the great work! I think you've got a really solid start here and you're poised to be able to add just tons of fun stuff.