diff --git a/strafe-client/src/physics_worker.rs b/strafe-client/src/physics_worker.rs
index 084d164..3acc292 100644
--- a/strafe-client/src/physics_worker.rs
+++ b/strafe-client/src/physics_worker.rs
@@ -57,8 +57,9 @@ pub fn new<'a>(
 			},
 			Instruction::Render=>{
 				run_session_instruction!(ins.time,SESSION_INSTRUCTION_IDLE);
-				let frame_state=session.get_frame_state(ins.time);
-				run_graphics_worker_instruction!(GraphicsInstruction::Render(frame_state));
+				if let Some(frame_state)=session.get_frame_state(ins.time){
+					run_graphics_worker_instruction!(GraphicsInstruction::Render(frame_state));
+				}
 			},
 			Instruction::Resize(physical_size)=>{
 				run_session_instruction!(ins.time,SESSION_INSTRUCTION_IDLE);
diff --git a/strafe-client/src/session.rs b/strafe-client/src/session.rs
index dc0b17a..137adbb 100644
--- a/strafe-client/src/session.rs
+++ b/strafe-client/src/session.rs
@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use strafesnet_common::gameplay_modes::{ModeId,StageId};
 use strafesnet_common::instruction::{InstructionConsumer,InstructionEmitter,InstructionFeedback,TimedInstruction};
 // session represents the non-hardware state of the client.
@@ -105,14 +107,27 @@ impl Replay{
 	}
 }
 
+#[derive(Clone,Copy,Hash,PartialEq,Eq)]
+struct BotId(u32);
+//#[derive(Clone,Copy,Hash,PartialEq,Eq)]
+//struct PlayerId(u32);
+
+enum ViewState{
+	Play,
+	//Spectate(PlayerId),
+	Replay(BotId),
+}
+
 pub struct Session{
 	user_settings:UserSettings,
 	mouse_interpolator:crate::mouse_interpolator::MouseInterpolator,
+	view_state:ViewState,
 	//gui:GuiState
 	simulation:Simulation,
 	// below fields not included in lite session
 	recording:Recording,
-	replays:Vec<Replay>,
+	//players:HashMap<PlayerId,Simulation>,
+	replays:HashMap<BotId,Replay>,
 }
 impl Session{
 	pub fn new(
@@ -123,8 +138,9 @@ impl Session{
 			user_settings,
 			mouse_interpolator:MouseInterpolator::new(),
 			simulation,
+			view_state:ViewState::Play,
 			recording:Default::default(),
-			replays:Vec::new(),
+			replays:HashMap::new(),
 		}
 	}
 	fn clear_recording(&mut self){
@@ -133,8 +149,13 @@ impl Session{
 	fn change_map(&mut self,map:&strafesnet_common::map::CompleteMap){
 		self.simulation.physics.generate_models(map);
 	}
-	pub fn get_frame_state(&self,time:SessionTime)->FrameState{
-		self.simulation.get_frame_state(time)
+	pub fn get_frame_state(&self,time:SessionTime)->Option<FrameState>{
+		match &self.view_state{
+			ViewState::Play=>Some(self.simulation.get_frame_state(time)),
+			ViewState::Replay(bot_id)=>self.replays.get(bot_id).map(|replay|
+				replay.simulation.get_frame_state(time)
+			),
+		}
 	}
 	pub fn user_settings(&self)->&UserSettings{
 		&self.user_settings
@@ -197,13 +218,37 @@ impl InstructionConsumer<Instruction<'_>> for Session{
 				_=self.simulation.timer.set_paused(ins.time,paused);
 			},
 			Instruction::Control(SessionControlInstruction::CopyRecordingIntoReplayAndSpectate)=>{
-				todo!();
+				// Bind: B
+
+				// pause simulation
+				_=self.simulation.timer.set_paused(ins.time,true);
+
+				// create recording
+				let mut recording=Recording::default();
+				recording.instructions.extend(self.recording.instructions.iter().cloned());
+
+				// create timer starting at first instruction (or zero if the list is empty)
+				let timer=Timer::unpaused(ins.time,recording.instructions.first().map_or(PhysicsTime::ZERO,|ins|ins.time));
+
+				// create default physics state
+				let simulation=Simulation::new(timer,Default::default());
+
+				// invent a new bot id and insert the replay
+				let bot_id=BotId(self.replays.len() as u32);
+				self.replays.insert(bot_id,Replay::new(
+					recording,
+					simulation,
+				));
+
+				// begin spectate
+				self.view_state=ViewState::Replay(bot_id);
 			},
 			Instruction::Control(SessionControlInstruction::StopSpectate)=>{
-				todo!();
+				_=self.simulation.timer.set_paused(ins.time,false);
+				self.view_state=ViewState::Play;
 			},
 			Instruction::Playback(_)=>{
-				todo!();
+				println!("[session] todo: Playback instructions");
 			},
 			Instruction::ChangeMap(complete_map)=>{
 				self.clear_recording();