Thanks for playing! Since uploading I have found that somehow there were exactly 3 map tiles without collision... no idea what happened there, but I have fixed it.
For being hit in the air, you may have fallen victim to a somewhat rare bug that has also been fixed in my local build. The fish from the main menu screen was triggering a jump signal that only the player fish should have been triggering. So if the main menu fish finished a jump when you were midair and hovering over a log or piece of trash, collision was turned back on and you got hit 😂
Not sure what the deal is with you not being able to jump while holding A and W though. Was this with the web or .exe build? And if the web, which browser?