My problem with the April Fools' maps is that they require so much work with so little payoff. Except for Link's Awakening Advance, I don't think there's been one that really fooled anyone who's familiar with the classics.
Because let's face it, if you've been playing games for a while you'll usually recognize re-used backgrounds and tiles, and original sprites just don't look good enough to be believable. I'm not saying that to belittle anyone's work, as I wouldn't even be able to do anything that looks close to a real game, but fan works often look and feel like fan works.
I must admit that I liked the idea of Oracle Of Hours, because even to someone who knew it wasn't real, it still looked like it could be.
To me, the ideal April Fools would either be maps for a totally original game based on an existing property (which would require real artistic talents and lots of work), or a long lost sequel. For example, if anyone had done the maps from Rockman 7 FC as an April Fools, *that* would have fooled a lot of people because the graphics feel like 8 bit versions of the SNES game, and the sprites are faithful NES adaptation of their 16 bit counterparts.
Anyway, I don't want to spoil this for anyone. Clearly, there are other mappers who love seeing and/or working on these, and anything that gets people mapping is a good idea. But, well, you now know my reasons for not helping, given how in addition to all I've said, I also want to keep mapping on my own.
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Current project: Not sure yet
Upcoming project: Not sure yet either