diff --git a/build.gradle b/build.gradle
index 1669e84..bc72a58 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,7 +7,7 @@ buildscript {
 
         aiVersion = '1.8.1'
 
-        artemisVersion = '1.4.0'
+        artemisVersion = '2.1.0'
         artemisContribVersion = '1.2.1'
         kryonetVersion = '2.22.0-RC1'
 
@@ -309,9 +309,6 @@ project(":desktop") {
 
             // Artemis-odb bonus functionality (systems, events, components).
             compile "net.mostlyoriginal.artemis-odb:contrib-core:$artemisContribVersion"
-            compile "net.mostlyoriginal.artemis-odb:contrib-jam:$artemisContribVersion"
-            compile "net.mostlyoriginal.artemis-odb:contrib-eventbus:$artemisContribVersion"
-            compile "net.mostlyoriginal.artemis-odb:contrib-plugin-operations:$artemisContribVersion"
 
             // jcommander for command line parsing
             compile "com.beust:jcommander:$jcommanderVersion"
diff --git a/core/src/com/ore/infinium/Inventory.kt b/core/src/com/ore/infinium/Inventory.kt
index f435530..746a304 100644
--- a/core/src/com/ore/infinium/Inventory.kt
+++ b/core/src/com/ore/infinium/Inventory.kt
@@ -63,8 +63,7 @@ open class Inventory
     }
 
     class InventorySlot(var entityId: Int,
-                        val slotType: InventorySlotType) {
-    }
+                        val slotType: InventorySlotType)
 
     var slots = mutableListOf<InventorySlot>()
         private set
@@ -197,6 +196,9 @@ open class Inventory
     private fun canCombineItems(itemId: Int, itemInSlotId: Int): Boolean {
         val itemComp1 = mItem.get(itemId)
         val itemComp2 = mItem.get(itemInSlotId)
+        if (itemComp2 == null) {
+            println()
+        }
         if (!itemComp1.canCombineWith(itemComp2)) {
             return false
         }
diff --git a/core/src/com/ore/infinium/systems/GameLoopSystemInvocationStrategy.kt b/core/src/com/ore/infinium/systems/GameLoopSystemInvocationStrategy.kt
index 4459380..76f9aad 100644
--- a/core/src/com/ore/infinium/systems/GameLoopSystemInvocationStrategy.kt
+++ b/core/src/com/ore/infinium/systems/GameLoopSystemInvocationStrategy.kt
@@ -110,7 +110,7 @@ class GameLoopSystemInvocationStrategy
                 profiler.counter.tick()
             }
 
-    override fun process(systems: Bag<BaseSystem>) {
+    override fun process() {
         if (!isServer) {
             //    frameProfiler.start()
         }
diff --git a/core/src/com/ore/infinium/systems/SpatialSystem.kt b/core/src/com/ore/infinium/systems/SpatialSystem.kt
index c44f805..7c4d7e3 100644
--- a/core/src/com/ore/infinium/systems/SpatialSystem.kt
+++ b/core/src/com/ore/infinium/systems/SpatialSystem.kt
@@ -58,7 +58,6 @@ class SpatialSystem(private val oreWorld: OreWorld) : IteratingSystem(Aspect.all
     var quadTree: QuadTree
 
     init {
-
         quadTree = QuadTree(0f, 0f, oreWorld.worldSize.width.toFloat(), oreWorld.worldSize.height.toFloat())
     }
 
diff --git a/core/src/com/ore/infinium/systems/client/ClientNetworkSystem.kt b/core/src/com/ore/infinium/systems/client/ClientNetworkSystem.kt
index a4f442b..e8b20ea 100644
--- a/core/src/com/ore/infinium/systems/client/ClientNetworkSystem.kt
+++ b/core/src/com/ore/infinium/systems/client/ClientNetworkSystem.kt
@@ -366,6 +366,8 @@ class ClientNetworkSystem(private val oreWorld: OreWorld) : BaseSystem() {
 
         val cItem = mItem.get(spawnedItemEntityId)
 
+        require(cItem.inventoryIndex != -1) { "told to spawn item at invalid index" }
+
         //fixme this indirection isn't so hot...
         inventory.setSlot(cItem.inventoryIndex, spawnedItemEntityId)
     }
@@ -470,7 +472,7 @@ class ClientNetworkSystem(private val oreWorld: OreWorld) : BaseSystem() {
                 sprite.setPosition(spawn.pos.x, spawn.pos.y)
             }
 
-            val cGenerator = mGenerator.getSafe(localEntityId)?.let {
+            val cGenerator = mGenerator.opt(localEntityId)?.let {
                 //recreate this on our end. since it is transient
                 it.fuelSources = GeneratorInventory(GeneratorInventory.MAX_SLOTS)
             }
diff --git a/core/src/com/ore/infinium/systems/server/ServerNetworkSystem.kt b/core/src/com/ore/infinium/systems/server/ServerNetworkSystem.kt
index 1bbfb8b..10e515d 100644
--- a/core/src/com/ore/infinium/systems/server/ServerNetworkSystem.kt
+++ b/core/src/com/ore/infinium/systems/server/ServerNetworkSystem.kt
@@ -368,13 +368,16 @@ class ServerNetworkSystem(private val oreWorld: OreWorld, private val oreServer:
                                 owningPlayerEntityId: Int,
                                 inventoryType: Network.Shared.InventoryType,
                                 causedByPickedUpItem: Boolean = false) {
-        //assert(entityIdsToSpawn.size > 0) { "entities to spawn in inventory should be non 0" }
+        require(entityIdsToSpawn.isNotEmpty()) { "entities to spawn in inventory should be non 0" }
 
         val spawn = Network.Server.SpawnInventoryItems()
         spawn.causedByPickedUpItem = causedByPickedUpItem
         spawn.typeOfInventory = inventoryType
 
         for (entityId in entityIdsToSpawn) {
+            val cItem = mItem.get(entityId)
+            require(cItem.inventoryIndex != -1) { "attempting to send invalid inventory index item spawn" }
+
             val entitySpawn = serializeInventoryEntitySpawn(entityId)
 
             spawn.entitiesToSpawn.add(entitySpawn)
diff --git a/core/src/com/ore/infinium/systems/server/ServerPowerSystem.kt b/core/src/com/ore/infinium/systems/server/ServerPowerSystem.kt
index 4d792d8..83fe9ad 100644
--- a/core/src/com/ore/infinium/systems/server/ServerPowerSystem.kt
+++ b/core/src/com/ore/infinium/systems/server/ServerPowerSystem.kt
@@ -96,7 +96,7 @@ class ServerPowerSystem(private val oreWorld: OreWorld) : IteratingSystem(anyOf(
     }
 
     private fun updateDevice(entityId: Int) {
-        val cGen = mPowerGenerator.getSafe(entityId)
+        val cGen = mPowerGenerator.opt(entityId)
 
         cGen?.let {
             when (cGen.type) {
diff --git a/core/src/com/ore/infinium/util/ArtemisExtensions.kt b/core/src/com/ore/infinium/util/ArtemisExtensions.kt
index fe6ce0c..dba006d 100644
--- a/core/src/com/ore/infinium/util/ArtemisExtensions.kt
+++ b/core/src/com/ore/infinium/util/ArtemisExtensions.kt
@@ -91,10 +91,6 @@ interface CopyableComponent<T : CopyableComponent<T>> {
 @Target(AnnotationTarget.PROPERTY, AnnotationTarget.PROPERTY_GETTER)
 annotation class DoNotPrint
 
-fun TagManager.getEntityId(tag: String): Int {
-    return this.getEntity(tag)!!.id
-}
-
 fun World.entities(aspect: Aspect.Builder): IntBag =
         this.aspectSubscriptionManager.get(aspect).entities