Read the review here.
“The miniature monsters are impressively classic, from the mythical Roc and Cerberus beasts to the Spring Heeled Jack and Manticore monsters, among many others, including even Tyrannosaurus Rex making an appearance.”
– from the full review, which you can read here.
I am not sure how to word this elegantly or even well, but I try in the full review a couple times (go read it!) and will try again now: Some NES games feel very average. Others, like Monster In My Pocket, are noticeably above-average, even if not mind-blowingly awesome. This is a perfect example of what a well-made platformer looks like from a high-quality developer; in this case, Konami. Is Monster In My Pocket one of the best video games of all time? No. But is it a very solid action platformer with a decent challenge curve, quirky distinctiveness, and a couple fun gameplay-mechanic flourishes (the double-jump, etc.)? Yes. Absolutely. Maybe the best way to understand what I am trying to say is to go try it yourself. This is a good game.
NES Gameplay Tips for Monster In My Pocket: Remember, the wave-slash remains animated on the screen for a split-second after pressing B; since you can attack fairly quickly again after an initial attack, you can actually somewhat form an impenetrable wall ahead of you by rapidly pressing the B button in the right rhythm. This is most useful with oncoming enemies, and very useful indeed for the ones about to dive-bomb you.
This game is guilty of newbie traps; you know, those parts of the game that kill players that are trying for the first time and cannot no any better. Thus, it pays to be paranoid and careful. Two examples: 1) On the staircase in the first level, or any other time you have the opportunity to jump off a structure into unseen territory of lower elevation off-screen, resist the urge to take a flying leap, as you will likely land on enemies. Instead, just step off and drop straight down. One instance of this tactic even rewards you with a key to help fight the horde ahead. 2) Some of the regular enemies take more than one hit to kill. The first example is those ugly troll guys that generate from the sewage flow in the third level. If you do not realize that they take two hits, you will probably take a point or two of damage in confusion, since it seems so odd at first, and there is not a significant indication (they just freeze for a brief moment with the first hit).
This is definitely a game where repeated playthroughs grant a much, much more significant chance of beating it. While that can likely be said for most games, this is more of an example than others; it is not as easy as something like Capcom’s Disney’s The Little Mermaid, which can be beat by a half-decent player on his first try, but neither is it as hard as something like Ninja Gaiden, where even passionate NES fans may still find massive difficulty beating that darn cartridge. Suffice to say, figuring out the boss patterns and how to get past those awful moving-platform portions will be a boon to future attempts. Good luck.