It's not really clear if you're going for a 16-bit or 8-bit throwback. You have colorful sprites, which indicates 16-bit. At the same time, the actual tile work is simple, which indicates 8-bit. So instead, you sort of have this mixed style and it looks rather careless.
So, two options.
If you're going 8-bit, do consider redrawing the sprites using a limited palette. No more than 20 colors, and also consider looking at some actual NES spritework before you do so, because it is a very distinct style and not immediately easy to emulate if that is the route you are taking.
If you're going for 16-bit style, again, stick to a limited palette. 52 colors or so*. Your art is displaying some very programmer art tendencies, and there are a lot of tutorials to help mitigate that, but sticking to a limited color scheme that you *use through* will keep things look a lot more consistent. Alternatively, if you want to vary the color scheme. And again, also consider looking at some actual 16-bit spritework and using that as a guide. Watch tiling. For instance, have at least four grass tiles and vary them up so it doesn't really look tiled, or, if sticking to a single grass tile, draw it in such a way that the tile boundaries aren't obvious. The video is a bit too grainy, unfortunately, to really tell what's going on with some of the tiles, but this looks like the case.
Similarly, in the ruined town, it might be to your benefit to have a couple dead tree sprites and vary them a little.
Also I want to draw attention to the world map, particularly the coastal regions. You have these blocky, tiled beaches. That doesn't really look good and wasn't hugely common in 8-bit games anyway.
http://www.mobygames.com/game/nes/final-fantasy/screenshots/gameShotId,31430/ FF1 smoothed coastlines a little, even, and PS1 smoothed them completely. FF1's forest regions are notable, too, for not being that blocky.
http://www.mobygames.com/game/nes/dragon-warrior-ii/screenshots/gameShotId,41831/ Even DQ2 did some work to smooth them out a bit, with the waves.
So, do attempt to aim for smooth transitions between biomes on your world map.
Is there any chance I could see an actual screenshot of the game?
I would also recommend toning down some of the referential humor. For instance, "Wise fwom yo gwave," or that SotN reference from the Troll King. It might be good for a couple of chuckles from a certain subset of the population, but the two references I saw in the video aren't particularly clever, and they ARE rather overdone. There's nothing that has to be INHERENTLY bad about making pop-culture references, especially in a parody game, but if they're too obvious they will, most likely, be more groan-worthy than funny.
One of the instances where this sort of humor works best is when it's surprising. When a reference is made that you wouldn't expect to be made in a million years. Context and set up also matter. If you have a lot of pop culture references coming in from nowhere with very little setup, it'll just seem bizarre.
Also, the SotN reference in particular doesn't really work since that was a 32-bit game and this is parodying 16/8-b it games. Consider instead, perhaps, having a wall monster that drops fried chickens that restore health or something. When people think of 8-bit castlevania games, meat randomly hidden in walls is what they'll probably remember more. It also has the added benefit of parodying the RPG tradition of having enemies that drop completely inappropriate items.
* A note on color limitations. I'm not sure what the actual palette limits for SNES and NES games were. I thought that the SNES ran under 256 colors, with 52 colors per tileset and up to 8 colors per sprite. Obviously, I'd recommend toning it even further down from there so that your art tended to maintain a distinct color scheme, at least per tile set. So... maybe limit your game to 52 colors total, with 26 colors per tileset, and 8 colors per sprite? Above all, do not use any colors that would be outside of the normal VGA 256 color range.
Here's some links.