I have to start with a caveat: reviewing a game that took me eleven months to play is a bit unfair to the game. There were several times when I stepped away from the game for months at a time, and each time I came back I had forgotten more of the story and characters. Eventually I’d piece 
things together but still I spent a lot of time reorienting myself to the game, and the lack of momentum with my game play hurt my sense of appreciation for some parts to the game. Nevertheless, I thought I’d offer up some thoughts on Final Fantasy IV.
Story
Wow! Following on the heels of Final Fantasy III—which seemed to be a game that in many ways forgot to add a story—Final Fantasy IV delivers a compelling story and a twisting plot. Combat drives Final Fantasy III, but the story drives Final Fantasy IV. Rich, detailed, and filled with character interaction, Final Fantasy IV sets the standard for the series so far in terms of quality story. Kudos!
Combat and Character Development
Coming on the heels of Final Fantasy III, with its complex job system and richly detailed combat, I have to say that the combat in Final Fantasy IV was a disappointment in many ways. Character classes are predetermined, and there is little to no gamer involvement in how characters develop.
This doesn’t mean that the game is necessarily a failure with regards to combat. Final Fantasy IV introduces the Active Time Battle system (ATB), which adds a real-time element to the combat. By nature, I like turn-based combat, so there was an adjustment curve for me here. Add in the fact that it can take me more time to read the Japanese and you end up with some stressful combat encounters in the first section of the game. 
However, once I got used to the system it worked fine. I actually found myself spending most of the game with the combat on the game’s fastest setting, and I appreciate that you can move through random encounters quickly. I wish, however, that you could change the speed setting mid-battle, as there were a few times when I unexpectedly ran into a boss battle with combat set on the highest speed and lost valuable seconds because of it.
I also like the combat balance in Final Fantasy IV. Battles were challenging at times, with enemies using a variety of strategies and moves that forced me to think in order to overcome them. For all its combat complexity, Final Fantasy III suffered because it had several jobs and attacks that were simply much stronger than the others. Despite the simplicity in Final Fantasy IV, I found myself forced to use a greater variety of spells and combat moves in order to succeed. Good stuff.
Game Balance and Progression
On the whole, Final Fantasy IV is the most balanced game in the series so far. The story stays focused and tight. I never felt totally lost or that things happened without cause or reason. Money did get meaningless at the end, but for the majority of the game funds were limited and I had to think about expenditures. Combat was mostly on the easy side, but overall was balanced and engaging, with only a couple of exceptions. Dungeons were of a reasonable size, and except for the last battle, I never felt like the save system hurt me that much.
Visuals
The graphics in Final Fantasy IV hardly compare to the updated and immersive graphics of Final Fantasy III, which of course leads the pack so far. 
With Final Fantasy IV, we’re back in the Game Boy Advance era. The graphics are functional, but not inspiring.
Save Me Now
I can’t get around this one: I hated getting killed by Zeromus, losing an hour’s worth of experience and fighting, and then having to do it all over again in order to get another shot at the guy. I realize I could have run from the random encounters at the end to speed things up, but I needed the experience. A game shouldn’t punish you and make you replay so much content just to get another chance for victory. A more modern save system would have been greatly appreciated.
Final Word
On the whole, I enjoyed Final Fantasy IV a lot. The great story and challenging combat kept me engaged the whole time. I honestly think I would have enjoyed it a lot more if I had played in straight through rather than playing it in chunks over the course of a year. It can be work to get back into a game after being away from it for a few months, and except for the beginning of the game, I never felt like I achieved any momentum with Final Fantasy IV, though no fault of its own. In the end, I have to give my experience with it an 85%, putting it in second place on the list so far. Well worth playing.
A few readers have posted that this may be an impossible task to complete accurately, but we were able continue our quest of keeping track of the total number of goblins killed in our Final Fantasy adventure. This was an easy task to do in Final Fantasy IV, as we have an easily accessible bestiary that records all our kills. Unfortunately, Final Fantasy IV had a rather tame sampling of goblins, and comes no where close to the impressive totals of the first two games.