When I picked up this game, I thought it would be a cute little diversion from my regular gaming. I was wrong.
You play as a Prinny, a cute demon penguin under the service of Lord Etna.
Your mission is to bring Etna the Ultimate Dessert, as her slightly-better-than-usual dessert has been stolen.
Etna has granted you a squad of 1,000 Prinnies to gather the ingredients. You play as one Prinny at a time, switching off when you die, therefore 1,000 Prinnies means 1,000 lives, and you will need them. These Prinnies are stronger than the "garden variety" Prinnies, in that they can take three hits, as opposed to one.
Story:
I just gave a basic summary of the story, it wouldn't be at all interesting if there weren't so many good jokes, aside from the story itself.
[ame="http://www.youtube.com/watch?v=cqVwF9KJU_s&feature=related"]YouTube - Prinny PSP - Touch my marshmallow[/ame]
Gameplay:
This is a platforming game, and the jumps generally require more focus than fighting off the enemies. When you think of how your Prinny jumps, think of Simon Belmont from Castlevania. When you press the jump button, you are committed to your landing point, the only ways to manipulate the path of jump are by using your second jump or by using a ground pound to bring you down in a straight line.
You can dash by charging up, then pressing a directional button before the charge leaves you temporarily stunned. This ability is cool, but it isn't required enough for you to remember it without falling to your death a few times, because you aren't jumping quite far enough.
The combat is simple, yet fun. You have the basic ground attack which can be pressed in rapid succession to combo. You also have an air attack that has several uses, you fire projectiles down at the ground when you press the attack button after setting up the attack, you also shift the view from side to somewhat behind, allowing you to see better what is up ahead.

Normal view.

Air attack view.
The air attack also slows down your descent.
Also, there is a combo meter, which fills up when you stun enemies with the ground pound attack.
Boss fights are fun, you must take away their 'shield points' to stun them so you can do effective damage.
[ame="http://www.youtube.com/watch?v=4Dbx29xzeC4&feature=related"]YouTube - prinny can i really be the hero - psp game play[/ame]
There is a central hub that gives access to the stages and secrets you have unlocked, also the hub contains a few secret items.
In some levels you can temporarily use vehicles to traverse terrain you couldn't normally. The vehicle control is decent, but nothing all that amazing.
Graphics: 4
The graphics engine uses 2D sprites for you, other characters and the enemies, and 3D for the playing field. The backdrops look hand painted.
The 2D sprites are amazingly detailed, and out-stage the 3D playing field. As a matter of fact, the 3D elements are bland and boring.
Sound: 4
The sound is good, the music is interesting and the voice acting is better than you might expect.
Music:
[ame="http://www.youtube.com/watch?v=cUfDr6qEANk&feature=related"]YouTube - Prinny- Going My Way[/ame]
[ame="http://www.youtube.com/watch?v=Vh0s2Rp12CI&feature=related"]YouTube - Prinny- Brave Heart[/ame]
[ame="http://www.youtube.com/watch?v=hR5Bs6riDEo&feature=related"]YouTube - Prinny- Dance With Me[/ame]
Voice:
[ame="http://www.youtube.com/watch?v=hvAAydskfF8"]YouTube - Intro - Prinny: Can I really be the hero?[/ame]
Replay: 4
You can unlock a second story, fight secret bosses, get secret endings, collect the secret data on each enemy and find the hidden dolls. You can also collect orbs that make characters show up in the hub, these characters provide enemy data and sound test modes, among other services. There are also medals to earn, and you can learn a secret move by losing all 1,000 lives.
[ame="http://www.youtube.com/watch?v=IJizIJk1EZI"]YouTube - Prinny Can I Really Be The Hero? Secret Skill "Prinny Raid"[/ame]
Challenge: 5
This game is hard, you will die. You can take three hits in normal mode and one in hard mode. You will probably lose at least 100 out of the 1,000 lives by the end of the game.
Final Thoughts:
This is a great game, a bit on the hard side. If you can get past the cutesy exterior, you will find a wholly satisfying gaming experience.