Except when you're going for the generic "8-bit look", where you can always reduce the amounts of pixels way down.
That also has an additional bonus: you can reduce the animations to a simple rotation movement (terraria) or a switch between two picture states (megaman-escue games and such), and everybody will praise you for "true authentic 90s experience".
True pixel art is hard, but that's not what all these developers are going for, isn't it?
This game? More like 16-bit. And fewer pixels doesn't always mean less work! >:c Communicating details when you only have 256 pixels to work with (in the case of 16x16 tiles) isn't easy!! >:v
^^This isn't a very good example (it's cluttered and it's hard to tell who he is and what he's holding without someone telling you), but it's 16x16 and most of my time working on this was spent adjusting pixels one at a time and trying to make details stand out, using 5 colors.
Just because someone is using pixels doesn't mean they're trying to make it look and play like a NES game. Some people want the aesthetic of pixels without all the work that comes with it. You bet your ass that devs back in the day would've used the tools we have now in order to make their jobs easier rather than impose artificial restrictions on themselves which would only make an their job harder. Unless you're trying to evoke that style, a dev isn't going to restrict his artist to 16 colors and no transparency if it means the game will work and look better. Memory isn't an issue like it was back then.
I think it's pretty obvious that this dev isn't trying to go for pixel purism, I think they set out
first to evoke an aesthetic, then they decided how to do it in the most efficient way possible, whilst keeping in line with the demands of the game's mechanics.