Such is the experience with Gradius Collection, a concentrated dose of retro awesome that is the kind of collection that older gamers wish for, just to show these whipper-snappers how good the older games were. All five Gradius games in the Collection occupy the same genre that doesn't necessarily need the graphics to keep them interesting a couple decades down the road: the almighty shoot-em-up, and though shmups have certainly gotten prettier (just look at something like Ikaruga), the simplistic visuals don't really hamper the game.
Then again, these were never games played for their graphics. Funky visuals, sure (it's hard to imagine a shooter that has more memorable stages like Gradius' volcanoes and Easter Island Moai heads), but not wildly amazing graphics. They're revered as (along with the R-Types as one the cornerstones of the shooter genre, and they're still amazingly good to this day.
Gradius is especially impressive, mainly because it's so simple, but the basic concepts of a single fighter going up against hordes of enemies with selectable power-ups still stands. Gradius II upped the ante by allowing you to select from different ship loadouts, added much better graphics and sound and generally just feels like a proper sequel. Gradius III refined this further by allowing you to actually choose your own loadout from some pre-selected lists, and Gradius Gaiden (which never saw release here in the States) cranks up the customization even more by allowing you to select when the weapons power-ups can be bought along the timeline. The final game, Gradius IV, actually steps back from things and plays more like Gradius II.
Though the difficulty through the timeline seems to follow something of a bell curve peaking at GIII (that may just be my familiarity with the games, and they do get easier the more you play them), Konami wisely plugged in a handful of improvements to make the game easier for newcomers. All of the games are certainly tough for anyone playing them for the first time, but there are options to add a "Tuned" PSP-specific version, set the difficulty lower (or higher), turn off slowdown, and even decrease the hitbox for your ship, allowing part of the top, bottom and front to actually hit things by a pixel or two without blowing up. Just for fun, the games can also be set to their normal resolution, zoomed to fill the screen vertically, or stretched to fill the whole 16:9 width of the PSP screen.
Being a compilation, it's actually something of a given that there would be some form of library or extras, just because that's something that's expected these days, but the ability to play music tracks and watch CG clips from the all the games is certainly appreciated. A couple of pages of the history of the series or some inside info from the original development team would have been really nice too, but it wasn't until I started playing these games again that I remembered how good the music was, and the game does give you the option to listen to all the track as your leisure.
I realize this is a fairly short review (especially for my overly verbose writing habits), but there's simply not a lot to say. Sure, I could play what-if with some of the games in the series that were spin-offs or quasi-sequels like Life Force or Sexy Parodius, but to be perfectly honest, the way these five games were handled is so respectful of the originals, and those games are so good that I don't really feel gypped in any way.
Konami knew what it was doing back in the day, knew how to take the simple concept of enemies that dropped power-ups and allowed you to add new weapons, shields, the ability to speed up and so on, but they were also groundbreaking in how they let the player pick and choose when to power-up the ship. (in the case of Gradius Gaiden you can actually power down if you need to). That this simple concept, coupled with great level design and some insanely difficult situations, stays as strong today as it was then is a testament to the longevity of the 2D shooter in general.
I honestly can't recommend this compilation enough. Sure, I can always want more games, but the emulation of what's here is awesome, the options make it so that even newcomers can get into the series, and old-schoolers have yet another game they can show off to younger gamers to prove even without the fancy-pants graphical effects, these games can still kick ass.