diff --git a/play.sh b/play.sh
index cc7c115..62f601c 100755
--- a/play.sh
+++ b/play.sh
@@ -1,3 +1,3 @@
 #!/usr/bin/env bash
 
-python src/main.py --replay_size 5 --play_games 1 --display_screen $*
+python src/main.py --replay_size 100 --play_games 1 --display_screen $*
diff --git a/profile_random.sh b/profile_random.sh
new file mode 100755
index 0000000..2ed5145
--- /dev/null
+++ b/profile_random.sh
@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# never explore, always predict
+python -m cProfile -s cumtime $* src/main.py --replay_size 100 --random_steps=1000 --train_steps=0 --test_steps=0 --epochs=1 roms/pong.bin
diff --git a/profile_test.sh b/profile_test.sh
index 0c20700..e8e1370 100755
--- a/profile_test.sh
+++ b/profile_test.sh
@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 
 # never explore, always predict
-python -m cProfile -s cumtime $* src/main.py --replay_size 5 --exploration_rate_test=0 --random_steps=0 --train_steps=0 --test_steps=1000 --epochs=1 roms/pong.bin
+python -m cProfile -s cumtime $* src/main.py --replay_size 100 --exploration_rate_test=0 --random_steps=0 --train_steps=0 --test_steps=1000 --epochs=1 roms/pong.bin
diff --git a/profile_train.sh b/profile_train.sh
index 3e2b6f0..649ecf2 100755
--- a/profile_train.sh
+++ b/profile_train.sh
@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 
 # predict all moves by random, to separate prediction and training time
-python -m cProfile -s cumtime $* src/main.py --exploration_rate_end=1 --replay_size 5 --random_steps=5 --train_steps=1000 --test_steps=0 --epochs=1 --train_frequency 1 --target_steps 0 roms/pong.bin
+python -m cProfile -s cumtime $* src/main.py --replay_size 100 --exploration_rate_end=1 --random_steps=5 --train_steps=1000 --test_steps=0 --epochs=1 --train_frequency 1 --target_steps 0 roms/pong.bin
diff --git a/src/main.py b/src/main.py
index 6c4ab03..59ddf9f 100644
--- a/src/main.py
+++ b/src/main.py
@@ -30,6 +30,8 @@
 memarg = parser.add_argument_group('Replay memory')
 memarg.add_argument("--replay_size", type=int, default=1000000, help="Maximum size of replay memory.")
 memarg.add_argument("--history_length", type=int, default=4, help="How many screen frames form a state.")
+memarg.add_argument("--min_reward", type=float, default=-1, help="Minimum reward.")
+memarg.add_argument("--max_reward", type=float, default=1, help="Maximum reward.")
 
 netarg = parser.add_argument_group('Deep Q-learning network')
 netarg.add_argument("--learning_rate", type=float, default=0.00025, help="Learning rate.")
diff --git a/src/replay_memory.py b/src/replay_memory.py
index 0365e8a..e06b8b8 100644
--- a/src/replay_memory.py
+++ b/src/replay_memory.py
@@ -14,6 +14,8 @@ def __init__(self, args):
     self.history_length = args.history_length
     self.dims = (args.screen_height, args.screen_width)
     self.batch_size = args.batch_size
+    self.min_reward = args.min_reward
+    self.max_reward = args.max_reward
     self.count = 0
     self.current = 0
 
@@ -27,6 +29,15 @@ def add(self, action, reward, screen, terminal):
     assert screen.shape == self.dims
     # NB! screen is post-state, after action and reward
     self.actions[self.current] = action
+    # clip reward between -1 and 1
+    if self.min_reward and reward < self.min_reward:
+      #logger.debug("Smaller than min_reward: %d" % reward)
+      reward = max(reward, self.min_reward)
+      #logger.info("After clipping: %d" % reward)
+    if self.max_reward and reward > self.max_reward:
+      #logger.debug("Bigger than max_reward: %d" % reward)
+      reward = min(reward, self.max_reward)
+      #logger.info("After clipping: %d" % reward)
     self.rewards[self.current] = reward
     self.screens[self.current, ...] = screen
     self.terminals[self.current] = terminal
@@ -61,10 +72,17 @@ def getMinibatch(self):
     while len(indexes) < self.batch_size:
       # find random index 
       while True:
+        # sample one index (ignore states wraping over 
         index = random.randint(self.history_length, self.count - 1)
-        # if does not wrap over episode end
-        if not self.terminals[(index - self.history_length):index].any():
-          break
+        # if wraps over current pointer, then get new one
+        if index >= self.current and index - self.history_length < self.current:
+          continue
+        # if wraps over episode end, then get new one
+        # NB! poststate (last screen) can be terminal state!
+        if self.terminals[(index - self.history_length):index].any():
+          continue
+        # otherwise use this index
+        break
       
       # NB! having index first is fastest in C-order matrices
       self.prestates[len(indexes), ...] = self.getState(index - 1)
diff --git a/test.sh b/test.sh
index f24b908..9834187 100755
--- a/test.sh
+++ b/test.sh
@@ -1,3 +1,3 @@
 #!/usr/bin/env bash
 
-python src/main.py --replay_size 5 --random_steps 0 --train_steps 0 --epochs 1 $*
+python src/main.py --replay_size 100 --random_steps 0 --train_steps 0 --epochs 1 $*