What's the difference between these three genres of games? Or are they all interchangeable terms? Is crystal war for example castle defense or is it an rts? What about plants vs zombies?
In my book i would make the following rough distinctions: Tower Defense: - a path leads to your `center` - enemies come on that aroundabout path to your center. - you place defense units along this path - the center itself is usually undefended and cannot be rebuild or upgraded. - you win when the enemy waves are defeated. - you lose after a certain number of enemies hit your center. example: geoDefense Castle Defense - you (try to) kill the enemies as they approach your castle in direct ways - with your only defense IS the castle. - you can level up your castle and it´s units etc. - when the enemy reaches your castle,they start to damage it but you still can kill them off. - you loose when the castle´s is destroyed. - you win by defeating the enemy waves. example: Besieged. Base Defense: - there are two opposite bases on the playfield. - throwing units at each other - which fight when they meet somewhere on the playfield - the winning unit moves on to the enemy base. - units level up, you base usually not. - the one destroying the enemies base first, wins. example: Alien9, Armageddon update: what they have in common is that they are usually in real time, not turn based. now these are the basic concepts only*. Some other games just bend the concepts as they see fit or add RTS and other management features. *neither complete nor ultimate
Tower Defense: Star Defense TowerMadness Sentinel 1 and 2 geoDefense and geoDefense Swarm Besieged Castle Defense: Knights Onrush ZombieSmash StickWars Castle Frenzy Base Defense: Castle Conflict Ancient War
Now Besieged is a Castle Defense, isn´t it? at least I build my specs list on it. And usually only castle-type buildings are ´besieged´