I'm impressed you made this in 48 hours! I've seen a full game with a similar interaction between retro worlds, (Mega Mash by Nitrome,) but that game had very distinct borders between worlds. Here, the worlds rip and tear at eachother, creating a very neat effect and causing some tricky and interesting gameplay. Unfortunately, I did encounter a bug here, where I fell from Otter Mario's world into an Otter Zelda lake and got stuck, but most such cases result in player death. However, I had to use the level skip cheat to get past levels 3 through 6. This had nothing to do with Otter Zelda or Otter Space Thing, both of which had fine gameplay and tight controls. The problem was Otter Mario, who controls like an otter coated in lubricant, slipping and sliding around the stage, off platforms, and into instakill pits. This was the character I had to use for star sections, where I'd need to travel a certain distance before the star wore off. The sharply limited time I had for this meant that I had to hurry, and I'd either slip once and thus not have enough time, or slide into a pit and have to start the level over. While at least the game is forgiving enough to give more stars, I still found that the timing requirement was beyond my capabilities. Still, there were plenty of fun little polish elements, such as the coin meter changing form depending on the nature of the game it's in, but it needs some tuning.