All systems go. Twenty years of "intense shooting action" locked and loaded. The weapon: a PSP disc by the name of Gradius Collection. The ammunition: five games from the series' past. Better run for cover, because this game is sniping and it's already hit the target.

Consisting of Gradius I through IV, plus the illusive, never-before-played Gradius Gaiden (a game that was not released outside of Japan until now), Gradius Collection is by far the best handheld space shooter available for the PSP. It could've won the title of "best" just by including the fourth game in the series. But as you'll quickly discover, this collection is more than just a conglomerate of five really good games.

Gradius, like the classic R-Type series, is a side-scrolling space shooter. Your ship is tiny, highly pervious, and almost insignificant in the alien-filled galaxies you about to explore. These aliens are unlike anything you've ever seen, with giant tentacles on some, and flame flowing through others. Bubbles form a dangerous barrier – one touch and you're toast. That's true of any hazard in this game. The only thing that's safe to touch is a power-up. Shields are available, but they don't last for very long.

Navigating through a cluster of slimy, snake-like creatures can be a bit overwhelming at first, especially if you're new to the genre. Quick reflexes seem to be the key, but patience turned out to be just as important. Sometimes it's not how fast you get away from an attack that matters, but rather how long you are willing to wait for the best opening (without freaking because a beam nearly hit you).

Bosses are big, moderately disgusting, and pleasantly destructive. Reveling in the essence of all legendary space shooters (including Gradius's own heritage), these monsters often have a multitude of attacks and one central weak point. Included in the attacks is large blast that means certain death if you're not prepared. The boss might opt for smaller blasts that strike from multiple angles, or a continuous flow of blasts that come from all angles. Or it might use tentacles or some other unpredictable attack that makes each of these classics hard to predict.

Gradius I

The original 1985 hit, Gradius loads just like its arcade brethren: with a 99-second countdown telling you that the game is warming up! Not to worry, it's just for fun and can be skipped.

Inside is a shooter that feels like R-Type with a slight hint of Galaga. Preliminary enemies swarm in a train-like pattern, with the leading alien guiding the pack. The music is also reminiscent of Namco's classic shooter, but the similarities stop there. In the 80s, game worlds rarely differed from shooter to shooter. It was the enemies and power-ups that defined each title, and that's where this game prevailed. Gradius had enough unique power-ups and enemy types to get (and keep) our attention. Twenty+ years later and it's still an undeniable, unrelenting classic.

Gradius II

Though it starts out as a bit of a rehash (as a way of paying homage to the original, perhaps?), Gradius II is a new beast with a new set of beasts, monsters, alien creatures, and other outer-space inhabitants who'd like to snack on your ship. Weapon selections are available from the start. You can also choose between having a shield or a force field as your only form of protection, which only kicks in once you've nabbed enough power-ups.

Whereas the original game was initially restricted to left and right movement (players could go up and down but a thick layer prevented them from moving beyond the area), Gradius II begins with a much larger playing field. Enemies take up more than the size of the screen, forcing you to move above or below the deadly beast to escape its wrath. Killing it is not an option, at least not entirely because someone decided to make its base impenetrable. Now you know who to scream at when you're playing the game: "Darn you, someone!"

Gradius III

This is the game that made me think, "The developers don't want me to beat this, do they?" It's only the third game in the series, but for me it's the most challenging. Hordes of enemies, laser balls, laser blasts, tons of unexpected attacks - it's almost too much! Dozens of new enemies and enemy attack styles make that much greater, while new weapon power-ups do little to cushion the blow. Strangely, for all the changes, Gradius III isn't much more graphically advanced than the first two.

Gradius IV

My favorite in the collection. This is the Super R-Type of Gradius games. It's faster, more exciting, and more refined. The controls are top-notch; by far the best in the series. The visuals have also been given a slight boost, with a higher resolution that fills more of the screen with more game and less pixelation. (See "Graphics" rating for more.) Basic enemies are essentially revised versions of those encountered in the previous games, while the rarer enemies are new and offer an unforeseen threat.

Gradius Gaiden

This is a solid shooter that's somewhat disappointing. It doesn't do anything significant that the others hadn't, nor is it as fast as Gradius IV or as challenging as Gradius III. I consider Gaiden a fun bonus since I would have wanted this collection whether it was included or not. But as a standalone title, it just doesn't live up to the series' standards.

Gameplay: 8.0
One of PSP’s best compilations and definitely its best space shooter, Gradius Collection is an intense experience that’ll make you say, “Just one more game” (about  times). The controls are rock solid, especially for the speedier iteration, Gradius IV. Boss battles are fun and never fail to infuriate upon failure, or satiate once complete.

Graphics: 6.0
Bottom-of-the-barrel, no-frills visuals that haven't been upgraded beyond a full-screen mode that stretches the picture, thus making the game look either blurry or pixelated (or both). Gradius IV handles this the best, but the rest are rather unfulfilling.

Sound: 6.9
Retro Gradius sounds. It’s never been my favorite part of this series, but the quality is decent and the nostalgia aspect is worth a few points.

Difficulty: Medium
Five solid, evenly challenging games. It's a fair challenge – you'll have to maneuver around as many bombs, beams, and deadly enemies as you do in other space shooters, minus the tremendous amount of frustration that comes with beating them. Gradius can be painfully unforgiving, but there's always a solution – and it's not based on dumb luck.

Concept: 7.0
Five Gradius games (including one that had never been released outside of Japan) ported to the PSP.

Overall: 8.0
Haven't played Gradius before? Gradius Collection is the perfect way to break into the series. It combines the best of the best for several dozen intense, challenging levels, each offering a unique array of enemy types to overcome. You can't beat Gradius III first thing and expect to conquer Gradius II no problem – this series doesn't work like that. Each game feels like an extension of the last, making this collection the perfect way to experience them.