I'm confident in saying that Conquest is one of the best Pokemon spinoff games out there. It's not without a few rough patches, but they don't necessarily take away from the gameplay.

The game's setting just works. Fictional feudal Japan, with a variety of kingdoms ruled by warlords who specialize in different Pokemon types. Conquering kingdoms and expanding your territory is just satisfying, plain and simple. The strategy gameplay is basically Fire Emblem, with a few Pokemon-related twists of its own. The artwork for the game is really great. All the warlords have unique and appealing designs, and all the artwork for the Pokemon themselves are fantastic (action pose!).

The sound quality is admittedly kinda crusty. Instruments and menu sound effects sound weirdly compressed or low-quality. Similarly, while I think the way the maps are rendered as 3D models looks nice, the Pokemon sprites look kinda weird. They're made to look like 3D models that can be viewed from multiple angles, but the moment the game zooms the camera in/out, they just kinda become pixel mush and the effect is lost (aka all the time).

Presentation flaws aside, this game is just worth it. The main campaign is more of a gatekeeper to the main meat of the game, which is like 30 "sidestories". If you wanted to, I have no doubt that you could play this game forever.