When I started listening to this disc, I had already been spoiled several times over by the Konami Battle the Best disc and was, for some reason, expecting something along those lines - screeching guitars, throbbing baselines, and unrelenting drums. That was my mistake. As this disc's music was done in the "grade up" style, where higher-grade synthesizers and some live instruments are used to reproduce original game songs, it couldn't really be expected to live up to the standards set by the Battle series. But once you accept it for what it is, Konami GM Hits Factory can be found to have its own unique strengths.
The disc starts out with a strong version of "In the Wind", the theme for the first half of Gradius III's third stage. This is a prime example of the grade-up method done right. There are solid drum effects, and the guitar is real (I think). It has not been fully orchestrated (or Metallica-ized), so it still maintains some of that "gamey" feeling, but it's still highly listenable. The same goes for the other two Gradius III songs, "Hit and Away" and "Legend", but doubly so for Legend. Its arrangement shucks the speedy action-oriented form of the original for one that emphasizes the majesty of the melody. While it may not stir you to start saying the pledge or anything, it is still very powerful, in a calm, quiet way.
The Dracula (Castlevania) tracks are good, although rather underwhelming. The grade-up here was done a little too literally, and some of the weaknesses of the original songs manifest themselves - sometimes painfully. This is especially true halfway through the live version of "Vampire Killer", which is actually more of a medly of the music from the very first Dracula game. These songs, like many on the disc, have a way of growing on you, though, and you may find yourself listening to them more than you might have thought.
Definitely the weakest parts of the disc are the A-Jax tracks. The synths used on these songs seem to be of lower grade than those used on the rest of the CD, and the melodies they play are rather plain. These songs retain too much of the gamey feel, and it cheapens the effect of the grade-up. Even on the new mix track, "Final Command", there are spots where the music almost says out loud, "I came from a late-'80s/early-'90s Japanese game, hear me roar."
The last game to be given a cover by this disc is Salamander, known as LifeForce stateside. Time was not very kind to these tracks either, but nostalgia may cause you to play them regularly. The grade-up itself was fine, sometimes exceptional, but not quite enough to make up for the dated songs.
In the end, this CD is a worthwhile buy if you like your arrangements graded up, or if you are a real fan of classic Konami game music. Otherwise, you may want to look to the Battle Series for something of a more dramatic change. If you want some rewarding listening that you almost have to study to truly appreciate, though, Konami GM Hits Factory II will keep you busy for quite a while.