I'm nearing the end of Super Mario World - I'm one stage away from Larry's castle, and I'm pretty sure that means I'm two stages away from Bowser's castle.
I unlocked Blue Yoshi by accident, and I find it kind of funny - the developers have all of these intricately designed puzzles based around timing your jumps and platforms that only move for a certain amount of seconds when you land on them, and yet give Mario a Cape Feather, go through the level on Blue Yoshi, and if the level contains any Koopa shells whatsoever, then it pretty much breaks all platforming challenges. I'm on one of the last levels of the game, and yet I was able to fly over 4/5 of it like I was playing Kirby.
I'm proud that I made it this far - Mario World is a game that I've been meaning to play for a while now (I've owned it for a while, but my cousins had a 100% save file, which made it tough to find the motivation to play it start to finish when I could play any level whenever I wanted), and aside from having to look up how to get out of the Forest of Illusion, it's been a ton of fun and an extremely well-designed game with no frustrating moments.
I've lost a lot of lives and taken a lot of hits, but it always felt fair, which is what I want out of a game. (as opposed to feeling like the developers wanted to screw the players over with annoying enemy placement, frustrating jumping mechanics, etc.)