1. I like it, it's quite soft and would be very pleasant, but your piano in the right hand is far too heavy sounding, and it's rather unsettling. What i mean by heavy is that it sounds too deliberate, like you're pressing very hard on each key. Think of it like a three-year-old trying to speak, compared to an adult speaking. The adult dances lightly through their speech, while the three-year-old pronounces every syllable carefully, deliberately, making it sound very broken. Likewise, when you play, you should be dancing over the keys, rather than pushing them so forcefully. (I have no idea if you actually played this or if you simulated it, but if it is simulated, you should go for a similar effect).
2. This one I actually liked a bit more than the first. The vibrating about a minute or so in sounds a bit odd, and the repetitive notes going down at about 2 minutes seem a bit squished and kind of mess up the rhythm, but other than that, I like it quite a bit. A very powerful piece.
3. This kind of reminds me of something you'd hear in Super Mario Galaxy at the beginning, and then we get into a very strong, regal type of song. I rather like this one too.
4. Hmm, this song somewhat gives me the type of sensation of a fable or ballad. It seems like you could put that as some kind of intro reel for your game. The loud part at the beginning startled me quite a bit, but I enjoyed it.
5. The beat in the intro was a bit weird. It felt like you had two conflicting rhythms. The soft part at 1:20 was possibly the best part of the whole song. The drum (?) thing you had going on there at some parts was nice, and very suspenseful. I can really see characters fighting to this song.
Overall, they were very well done, and you were successful in the way that your songs made me want to play your game. You seem to have some pretty good potential as a composer. You can come to me if you need any more feedback, because feedback and critique is what I do best. You can also go to the Post Your Music thread we have here. It's made for composers to get feedback.