I have no idea what you're trying to say here.
The sub-pixeling in the idle here plays with my eyes, maybe it's just me.
I think the idle animation is great, and I don't think he used too many frames... I think it's 8 frames, but really only 4(1-2-3-4-3-2-1). Either way, depending on how skilled he is(and I can only assume from his others that he is very skilled in animation), that may not be a lot of work.
I wasn't referring to his idle animation, so I should clarify. What I have noticed about his animations is that they are all extremely animated, which is fun to show off such a skill, but sometimes it's not always necessary.
Whatever exactly sub-pixeling is, I haven't seen it before (at least I haven't noticed it). If I did, it probably was used sparingly deliberately so I would not notice it. Of course though, I have played little to no games around when the GameCube and GameBoy Advance first appeared, if it is a new style. I also never played Metroid, so maybe I'll give it a try sometime and tell you if I agree about the subtle sub-pixel animation. Everybody has their own taste in style (part of mine is try not to screw with your eyes), as they do in everything.
Regardless, workload shouldn't be a negative, and you shouldn't deter people from putting time into their work. Games like Metroid always have great animation and even the idle position has animation(much like his, has subpixel animation). I don't think workload or time consumption is ever really up for critique because it's completely up to the person how much time they want to put into their work.
You misunderstand, I am not critiquing his workload, or any other artists' who want to take their time for perfection sake. However, speaking from experience making games in my spare time, sometimes you have to speed up your workload, especially if you are both the programmer and the artist. That is, if you want to release it or bump it to a full version in a reasonable, yet still long, date.
If he
and his friend can create good art pretty quickly, then good. It's totally up to the artist to manager their free time. Nobody has to take my advice if he/she doesn't wish to. It's just my preference when creating games for the sake of allowing me to program more.