Patience makes perfect.
It is easy to take a tower defense title at face value. Most of the time, they are a simple variant on the standard tower defense formula with an easily identifiable twist. The twist in the DSiWare's Dairojo! Samurai Defenders, however, isn't apparent until you have seen the game over screen... for the tenth time.
As you may have suspected, the big twist with Samurai Defenders is that it is wretchedly difficult. At a glance, the game appears to simply be what we all expect from tower defense with a Japanese medieval motif, this makes Samurai Defenders simple to pick up and play. You place defensive units along a path that leads towards the tower with the hopes that your units will be able to eliminate the enemy waves before they can reach the tower gates.
Player units range from spearmen, who can stab enemies from a short distance, to archers that specialize in destroying enemy air units, and generals that boost nearby allies' attack power. Each unit can be upgraded during the progression of a level at the cost of in-game currency dropped by fallen enemies.
The familiarity of Samurai Defenders will trick players at the outset. After struggling to clear even the lowest level normal mission, I can certainly say that Samurai Defender's difficulty will shock nearly everyone who picks it up. Enemies will fly unpredictably from random sides of the screen directly towards the tower, potentially bypassing all of your defenses, and almost always forcing you to restart the level entirely. This wouldn't be disruptive, but the game forces you to play through 99 waves of enemies per level sans checkpoints or quick saves.
This structure, 99 uninterrupted waves of enemies, is shared between the game's three single player variants: score attack, normal, and random. Each of the game's modes actually feature the same level designs, but change how enemies appear and how the player is scored. Playing a level again in a different mode, then, isn't very compelling.
Daijoro Samurai Defenders isn't entirely lacking in creativity. Players can deploy some helpful power ups in battle, and the game features local multiplayer.
There is nothing inherently challenging about the mechanics of Samurai Defenders, because it is ultimately the same tower defense game we have all played before. It is simply the endurance that the game requires, combined with unpredictable enemy waves that make it not only a frustrating experience, but a poor portable experience as well.