Video game music can be the best part of a game. It's one of the prime components to the aesthetics of a game and can really contribute to the soul's wholeety. A game's music is the foundation for the tone, having as much (if not more) of an impact on the atmosphere than the visuals. This being said, the music can indicate what kind of game you'll think it's going to be.
If the music is happy or campy, then you might get the sense that the game is supposed to be light-hearted and joyful, just there for you to have a good time. If the music is slow, solemn, or dark, you might catch the vibe that you're getting into something serious, with an oppressive atmosphere. If the music to a game does not fit, it can all just make the game feel off. It might not take away from the game, but there is always the possibility.
Chip-tune is easy to replicate via humming, and if a piece is catchy it's also easy to replicate by humming. If you can hum it enough, it tends to become memorable.
Some ind games don't require music, requiring only sound effects, miscellaneous noises, and maybe the occasional bit of ambience here and there. Expertly done examples of this would be Ditto and Fallout New Vegas' Add-on Dead Money. Ditto has a very calm yet dark and oppressive tone, and the silence broken my only the sound effects and the occasional water drip drives this home. Dead Money is meant to be scary. It's ambience with random noises emphasize this the utmost degree, working with the visuals to purposely unnerve you at your core. Boy does it do it well.
Back in the day, when the music was ever so hindered by the technology of the age, music had to resort to much simpler means to convey atmosphere. They couldn't use the detailed compositions of today's music. Heck, they couldn't really get anything to sound like instruments. Instead, they composed strong melodies out of compressed sound bits that make the chip-tune style unique. These strong melodies are simple, and usually catchy. It's because they're catchy that they tend to be more memorable. Chip-tune is easy to replicate via humming, and if a piece is catchy it's also easy to replicate by humming. If you can hum it enough, it tends to become memorable. Also, it's simple nature allows you to remember it easier, but that does not involve humming so it's boring so whatever.
Some games can have pleasant and fitting music that just isn't that memorable. You may remember it when you hear it, but you just can't quite recall how it goes on your own. These tend to be in the ambient side of things. Fez is big on this. It doesn't really use any strong melodies, just random notes that fit the tone it's trying to convey. This type of music is usually slow-paced, providing enough space in-between chords so that it doesn't just sound like an inconceivable jumble of sounds. This type of music is by no means bad, as it can be very fitting within the game it plays during. It simply isn't near as impact full to listen to outside of the game is all.
The door is open for amazing things in the realm of video game composition, but remember that with great power, comes great responsibility.
Well as time moved on games gained access to quality sounding instruments, as well as other advancements in the music field. The floodgate of variety for musical feats one could now accomplish was open. Gaming now has ways to pull off awesome things with it's music, and it's awesome. Some might still stick to the chip-tune style, updating it and making use of the complexity they can achieve with today's technology. The door is open for amazing things in the realm of video game composition, but remember that with great power, comes great responsibility. Lets hope future video video game music doesn't mess things up.