Destroy them all!
There are five games in all in this collection, which includes: Gradius, Gradius II, Gradius III, Gradius IV and finally Gradius Gaiden. All the games are straight ports of their counter-parts, Gaiden being from the playstation and the rest from the arcades.
The Gradius games are played out horizontally, in which you control a ship (Vic Viper) and navigate through many level-filled environments, packed with enemies. One notable feature that makes Gradius standout from other games is the power-up system. On the bottom section of the screen, lists a chart of what power-ups you can get. By destroying enemies (the orange versions of them) they will leave an orange capsules, as you pick it up, you will have a power-up highlighted on the left, picking up more will move it to the right with a different power-up being highlighted. When you activate the power-up, the highlighted power-up will reset. The power-ups range from speeding up your ship to adding more firepower and options to your ship. There is also a semi-auto for your power-ups, which will activate power-ups automatically as you collect the power capsules, though it’s not recommended because it will probably conflict in what power-ups you really want.
The first Gradius is over twenty years old and it still a good game in its own right. Though, the later versions improve upon the game and its formula. Gradius is also on the short side compared to the rest of the collection.
Gradius II improves over the first one by including a weapon select, which have different sets of power-ups. Ranging from different shot attacks and missiles. Also included is the choice between the types of different shields: force field and shield. One of the major improvements over the first one would be the stage design. It is more unique, ranging from fire dragons that come from fiery stars and floating glaciers that collide and bounce around.
Next up is Gradius III, which is not the SNES version but the arcade version which has different stages and layouts. Another thing that differs from the SNES version is difficulty. The difficulty in this game is so high that it feels really "cheap" in a way, at the start of the stage, enemies and bullets will literally fill up the screen. Gradius III also features the edit mode, which allows you to customize the types of power-ups you want.
Gradius IV is somewhat of a step backwards because of the removal of the edit mode, and back to the weapon select with set power-ups. The game has also borrowed and recycled similar stage layouts from past Gradius games, though it doesn't really detract from the quaility of the game.
Lastly, Gradius Gaiden which is one of the best Gradius games! Gaiden allows you to choose among 4 different ships with their own set of power-ups. They have different types of shots and missiles, that it will actually make you play them quite differently, which is a huge plus. Gaiden also includes a gauge edit, which allows you to reorder the power-ups. The stage layout and bosses are one of the best in the series!
The collection also has a save feature which allows you to save anywhere in the game. You can save, load and resume as much as you want. Though, you do not really leave off where you last saved, instead the game puts you in certain check points. Another screwing thing about it is you can play a certain section to get power-ups, save, reload and repeat to get more power-ups. However, you do not have to use this feature, if you don't want to.
Gradius, Gradius II and Gradius III look and sound, well quite old. Decades actually but they still hold up today and really add to the whole nostalgic factor while you play it. Gradius IV and Gaiden are quite the opposite and have that well polish look. Each of the games also has different types of screen formats ranging from the default arcade display and stretch/wide to fit the PSP, which is meant for this game.
This collection also has a gallery mode where you can listen to BGM of each stage of each game. Also listed is a movie player where you can view FMV intros of other Gradius compilations. You may think the games are quite short and may last you a couple of hours each, this may be true; however, as you clear a game, the game actually loops back to the beginning with a much higher difficulty.
All in all, this is a great compilation for fans and also people who can appreciate simple yet challenging game play.