This plugin adds - as the title says - improvements to MineCraft's Survival gameplay. These features include mini-bosses, gravestones and economy.
Bosses
Video:
The bosses in this plugin are encountered by breaking a spawner of their type. Currently, zombie, skeleton, (cave) spider and blaze are available. All bosses have special gear they drop on death:
Zombie drops a sword with good enchants and a chestpiece with protection.
Skeleton drops a bow with good enchants and a helmet with knockback resistance
Spider drops a poisoning sword and leggings that speed you up when worn.
Blaze drops a flaming sword and boots that increase your health.
The difficulty and enchants of the drops are dependent on the number of kills the player has made on its mob type and can be customized in the configuration file.
Gravestones
Using this plugin, when a player dies, he will instead of dropping his stuff, drop a gravestone with a countdown. The gravestone can only be destroyed by the player that dropped it or a server operator. When it is destroyed, the player will get his stuff back. There is also a countdown on the gravestone, which will automatically break the gravestone when it reaches zero.
Economy
Not fully completed yet
The economy system of Survival Improvements will add the possibility to get money from killing mobs or other players. Also, you will be able to lose money upon death. Currently, the plugin does only support its own economy system. I will add more possibilities in a alter update.
/boss <type> <level> will spawn a boss without breaking a spawner (only for testing purposes)
/sireload will reload the configuration files.
/sistats <player> will view a player's stats in JSON format.
/attribute <type> <value> <operation> <name> will add an attribute to the item in your hand. More information can be found on http://minecraft.gamepedia.com/Attribute