Everyone always brings up Mushihimesama, DoDonpachi, or Death Smiles while discussing CAVE games, entirely ignoring Espgaluda, which is a complete crime against humanity.

Here's the gimmick: You have two shooting styles: the primary one, which is just your usual, straightforward type, and the secondary one, which activates "slow mode." While in slow mode, enemy projectiles will become much slower, making it easier to avoid them, and your projectiles will deal significantly more damage. The catch is that in order to activate slow mode, you'll need to collect emeralds, which can only be acquired by destroying enemies with your primary shooting type. This forces you to use your primary shooting style most of the time, destroy as many enemies as you can, and get familiar with every stage, using slow mode only when necessary. In fact, abusing slow mode will lead to the exact opposite effect: enemy projectiles will get much, much faster, making them almost impossible to dodge. This mechanic has so much depth and allows for so much experimentation that it alone makes subsequent playthroughs worth it. I'm still discovering little tricks. 

On top of that, its action, coreography, and enemy projectiles are all so well crafted and thought out, so above much popular shmups that it makes me wonder... Why does this one not get the praise it deserves? 

The music is also fantastic. I'm not a big fan of techno but shit slaps.

There aren't many games in the already small Sega CD catalog that are universally praised, such as this one, so I gotta admit, I started Popful Mail with very high expectations, and to be honest with you, I ended up crushing into a wall.

If there's one way to describe 'Popful Mail', it would be clunky. You only have one attack that goes straight ahead, and since many enemies are usually either above or below you, it makes them really hard to hit. Enemy hitboxes in themselves are also random, which becomes a huge problem, especially in the fire prision scene. Here, you'll be forced to defeat a number of little flame enemies in order to escape while you are on a timer, and since their hitboxes are so finnicky and the time window to hit them so small, you can absolutely get stuck here, dying over and over again without being your fault. The worst, however, are the boss battles; all of them are basically the same: A big enemy that's going from left to right, waiting to be hit—some jump from left to right, some fly from left to right, some of them move only in one direction, and some don't move at all to try to change things up. It just gets old really quick. You can change characters at any given time, and you'd think this would offer more variety or a significant change in gameplay, but they are basically all the same. They also made the really weird decision not to set a fixed camera in the middle of your character, setting a 'dynamic' one instead that just scrolls when you are on either its far left or far right, so bumping into enemies is really common, such a strange oddity.

Where this game excels is in its presentation. Character sprites and animations are outstanding; the cut scenes are super impressive for their time; and the fantasy world with its comedic tone reminded me of something like Slayers. The voice acting is probably the best thing this game has to offer. Every character feels so alive, and their characterization is spot on. I don't lie when I say characters like Sven or Slick made the whole game for me; they have no right to be that funny.

The game, however, is mediocre at best. I'd still give it a chance for the story and characters alone; just don't expect thrilling gameplay.