diff --git a/LICENSE.txt b/LICENSE.txt
index 7edcd1e..7c6e187 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2018 - Marcos Cardinot <marcos@cardinot.net>
+Copyright (c) 2023 - Marcos Cardinot <marcos@cardinot.net>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/example.jpg b/example.jpg
deleted file mode 100644
index 2bd9247..0000000
Binary files a/example.jpg and /dev/null differ
diff --git a/metadata.json b/metadata.json
index 43c9871..3940bf7 100644
--- a/metadata.json
+++ b/metadata.json
@@ -1,16 +1,19 @@
 {
   "type": "model",
-  "uid": "prisonersDilemma",
+  "uid": "prisonersDilemmaExtended",
   "version": 1,
-  "title": "Prisoner's Dilemma Game",
+  "title": "Extended Prisoner's Dilemma Game",
   "author": "Marcos Cardinot",
-  "description": "It implements the experiment proposed by Nowak, M. A., & May, R. M. (1992). Evolutionary games and spatial chaos. Nature, 359(6398), 826. DOI: http://dx.doi.org/10.1038/359826a0",
+  "description": "It implements a generalized version of the experiment proposed by Nowak, M. A., & May, R. M. (1992). Evolutionary games and spatial chaos. Nature, 359(6398), 826. DOI: http://dx.doi.org/10.1038/359826a0",
   "supportedGraphs": ["squareGrid","edgesFromFile"],
   "pluginAttributesScope": [
-    {"temptation": "double[1,2]"}
+    {"cc": "double[-1000,1000]"},
+    {"cd": "double[-1000,1000]"},
+    {"dc": "double[-1000,1000]"},
+    {"dd": "double[-1000,1000]"}
   ],
   "nodeAttributesScope": [
     {"strategy": "int{0,1,2,3}"},
-    {"score": "double[0,16]"}
+    {"score": "double[-100000,100000]"}
   ]
 }
diff --git a/plugin.cpp b/plugin.cpp
index dff8eec..a0cfea7 100644
--- a/plugin.cpp
+++ b/plugin.cpp
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2018 - Marcos Cardinot <marcos@cardinot.net>
+ * Copyright (c) 2023 - Marcos Cardinot <marcos@cardinot.net>
  *
  * This source code is licensed under the MIT license found in
  * the LICENSE file in the root directory of this source tree.
@@ -11,8 +11,16 @@ namespace evoplex {
 
 bool PDGame::init()
 {
-    m_temptation = attr("temptation", -1.0).toDouble();
-    return m_temptation >=1.0 && m_temptation <= 2.0;
+    const auto read = [this](auto& var, const auto& strategy)
+    {
+        var = attr(strategy, -999999.).toDouble();
+        if (var < -1000. || var > 1000.) {
+            qDebug() << "Invalid payoff! " << strategy << var;
+            return false;
+        }
+        return true;
+    };
+    return read(m_cc, "cc") && read(m_cd, "cd") && read(m_dc, "dc") && read(m_dd, "dd");
 }
 
 bool PDGame::algorithmStep()
@@ -62,10 +70,10 @@ bool PDGame::algorithmStep()
 double PDGame::playGame(const int sX, const int sY) const
 {
     switch (binarize(sX) * 2 + binarize(sY)) {
-    case 0: return 1.0;             // CC : Reward for mutual cooperation
-    case 1: return 0.0;             // CD : Sucker's payoff
-    case 2: return m_temptation;    // DC : Temptation to defect
-    case 3: return 0.0;             // DD : Punishment for mutual defection
+    case 0: return m_cc;    // CC : Reward for mutual cooperation
+    case 1: return m_cd;    // CD : Sucker's payoff
+    case 2: return m_dc;    // DC : Temptation to defect
+    case 3: return m_dd;    // DD : Punishment for mutual defection
     default: qFatal("Error! strategy should be 0 or 1!");
     }
 }
diff --git a/plugin.h b/plugin.h
index e1ae2e8..c897d28 100644
--- a/plugin.h
+++ b/plugin.h
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2018 - Marcos Cardinot <marcos@cardinot.net>
+ * Copyright (c) 2023 - Marcos Cardinot <marcos@cardinot.net>
  *
  * This source code is licensed under the MIT license found in
  * the LICENSE file in the root directory of this source tree.
@@ -20,7 +20,10 @@ class PDGame: public AbstractModel
 private:
     enum NodeAttr { STRATEGY, SCORE };
 
-    double m_temptation;
+    double m_cc;
+    double m_cd;
+    double m_dc;
+    double m_dd;
 
     double playGame(const int sX, const int sY) const;
     int binarize(const int strategy) const;