adding in some needed packages

Assets/Bremsengine/Time Slow Handler/TimeSlowHandler.cs

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+using System.Collections.Generic;
+using UnityEngine;
+
+namespace Bremsengine
+{
+    public class TimeSlowHandler : MonoBehaviour
+    {
+        static TimeSlowHandler Instance;
+        public class SlowdownEntry
+        {
+            public SlowdownEntry(float amount, float duration)
+            {
+                this.slowdown = amount;
+                this.remainingDuration = duration;
+            }
+            public float slowdown;
+            public float remainingDuration;
+        }
+        bool isPaused;
+        static List<SlowdownEntry> timeSlow = new();
+        public static float SlowdownHandledTimescale => Instance == null ? 1f : calculatedTimescale;
+        private static float calculatedTimescale;
+        private void Update()
+        {
+            SlowdownEntry item;
+            for (var i = 0; i < timeSlow.Count; i++)
+            {
+                item = timeSlow[i];
+                item.remainingDuration -= Time.unscaledDeltaTime;
+                if (item.remainingDuration <= 0f)
+                {
+                    timeSlow.RemoveAt(i);
+                    i--;
+                }
+            }
+            calculatedTimescale = GetTimescale();
+        }
+        public static void AddSlow(float amount, float length)
+        {
+            if (Instance == null || Instance.gameObject == null)
+            {
+                GameObject g = new GameObject("Time Slow Handler");
+                Instance = g.AddComponent<TimeSlowHandler>();
+            }
+            timeSlow.Add(new SlowdownEntry(amount, length));
+        }
+        private void OnDestroy()
+        {
+            if (Instance == this)
+            {
+                Instance = null;
+            }
+        }
+        private float GetTimescale()
+        {
+            if (isPaused)
+                return 0f;
+            float highestSpeedup = 1f;
+            float lowestTimeSlow = 1f;
+            foreach (var entry in timeSlow)
+            {
+                if (entry.slowdown < lowestTimeSlow)
+                {
+                    lowestTimeSlow = entry.slowdown;
+                }
+                if (entry.slowdown > highestSpeedup)
+                {
+                    highestSpeedup = entry.slowdown;
+                }
+            }
+            return lowestTimeSlow * highestSpeedup;
+        }
+    }
+}