yeah you're going straight to hell

Assets/Prefabs/Projectile Count Upgrade.asset

@@ -0,0 +1,18 @@
+%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!114 &11400000
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: abe88be260cd4b175b742754eaee097f, type: 3}
+  m_Name: Projectile Count Upgrade
+  m_EditorClassIdentifier: 
+  upgradeName: Projectile Count Upgrade
+  upgradeIcon: {fileID: 0}
+  thisPlayerAbility: {fileID: 0}
+  count: 1

Assets/Prefabs/Projectile Count Upgrade.asset.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 6fe34d7ec95c2ce1fac0727c553b5f0b
+NativeFormatImporter:
+  externalObjects: {}
+  mainObjectFileID: 11400000
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/AbilityManager.cs

@@ -0,0 +1,66 @@
+using System;
+using UnityEngine;
+using UnityEngine.UI;
+
+public class AbilityManager : MonoBehaviour
+{
+    #region Statication
+
+    public static AbilityManager instance;
+
+    private void Awake()
+    {
+        if (instance != null && instance != this)
+        {
+            Destroy(gameObject);
+            return;
+        }
+        instance = this;
+    }
+
+    #endregion
+    public MarisaAbilityHandler player;
+    public AbilityUpgrade upgradeToAdd;
+    public Button upgradeButton;
+    private void Start()
+    {
+        upgradeButton.onClick.AddListener((() => AddUpgrade(upgradeToAdd, player.mainAttackInstance)));
+    }
+
+    public void AddUpgrade(AbilityUpgrade upgrade, PlayerAbility ability)
+    {
+        if (!ability.attachedUpgrades.Contains(upgrade))
+        {
+            AbilityUpgrade newUpgrade = Instantiate(upgrade, ability.transform);
+            ability.attachedUpgrades.Add(newUpgrade);
+            newUpgrade.thisPlayerAbility = ability;
+            newUpgrade.ApplyUpgrade();
+        }
+        else
+        {
+            ability.attachedUpgrades.TryGetValue(upgrade, out AbilityUpgrade foundUpgrade);
+            if (foundUpgrade)
+            {
+                foundUpgrade.count++;
+                foundUpgrade.ApplyUpgrade();
+            }
+        }
+    }
+
+    public void RemoveUpgrade(AbilityUpgrade upgrade, PlayerAbility ability)
+    {
+        if (ability.attachedUpgrades.TryGetValue(upgrade, out AbilityUpgrade foundUpgrade))
+        {
+            if (foundUpgrade.count > 1)
+            {
+                foundUpgrade.ApplyRemoval();
+                foundUpgrade.count--;
+            }
+            else
+            {
+                foundUpgrade.ApplyRemoval();
+                ability.attachedUpgrades.Remove(foundUpgrade);
+            }
+        }
+    }
+}

Assets/Scripts/AbilityManager.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 1536116e866f6604e8d93d80bb9a6237

Assets/Scripts/AbilityUIHandler.cs

@@ -1,16 +1,22 @@
+using System;
+using System.Collections.Generic;
 using UnityEngine;
 
 public class AbilityUIHandler : MonoBehaviour
 {
-    // Start is called once before the first execution of Update after the MonoBehaviour is created
-    void Start()
+    public List<AbilityUIObject> uiObjects = new();
+
+    [SerializeField] private MarisaAbilityHandler playerAbilityHandler;
+
+    private void Start()
     {
-        
-    }
-
-    // Update is called once per frame
-    void Update()
+        uiObjects[0].thisAbility = playerAbilityHandler.mainAttackInstance;
+        uiObjects[1].thisAbility = playerAbilityHandler.secondaryAttackInstance;
+        uiObjects[2].thisAbility = playerAbilityHandler.spellAInstance;
+        uiObjects[3].thisAbility = playerAbilityHandler.spellBInstance;
+        foreach (AbilityUIObject uiObject in uiObjects)
         {
-        
+            uiObject.UpdateUI();
+        }
     }
 }

Assets/Scripts/AbilityUIObject.cs

@@ -8,24 +8,45 @@ public class AbilityUIObject : MonoBehaviour
     [Header("Ability Identification")]
     [SerializeField] private Image abilityIcon;
     [SerializeField] private TextMeshProUGUI abilityName;
+    
     [Header("Ability Stats")]
     [SerializeField] private TextMeshProUGUI damage;
     [SerializeField] private TextMeshProUGUI fireRate;
     [SerializeField] private TextMeshProUGUI piercing;
     [SerializeField] private TextMeshProUGUI projectileCount;
     [Header("Upgrades")] 
-    [SerializeField] private List<Transform> upgradeBoxes = new();
+    [SerializeField] private UpgradeBoxUI templateUpgradeBox;
+    [SerializeField] private Transform upgradeGrid;
+    [SerializeField] private List<UpgradeBoxUI> upgradeBoxes = new();
     
-    public void UpdateUI(PlayerAbility ability)
+    public PlayerAbility thisAbility;
+
+    public void UpdateUI()
     {
-        abilityIcon.sprite = ability.abilityIcon;
-        abilityName.text = ability.abilityName;
-        damage.text = $"Damage: {ability.power}";
-        fireRate.text = $"Fire rate: {ability.cooldown}s";
-        if (ability.TryGetComponent(out FireBullet isBullet))
+        abilityIcon.sprite = thisAbility.abilityIcon;
+        abilityName.text = thisAbility.abilityName;
+        damage.text = $"Damage: {thisAbility.power}";
+        fireRate.text = $"Fire rate: {thisAbility.cooldown}s";
+        if (thisAbility.TryGetComponent(out FireBullet isBullet))
         {
             piercing.text = $"Piercing: {isBullet.pierceAmount}";
             projectileCount.text = $"Projectiles: {isBullet.projectileCount}";
         }
     }
+
+    public void AddUpgradeBox(AbilityUpgrade upgrade)
+    {
+        UpgradeBoxUI newBox = Instantiate(templateUpgradeBox, upgradeGrid);
+        upgradeBoxes.Add(newBox);
+        newBox.upgradeImage.sprite = upgrade.upgradeIcon;
+        newBox.UpdateCounter();
+    }
+
+    public void UpdateUpgradeBoxes()
+    {
+        foreach (UpgradeBoxUI box in upgradeBoxes)
+        {
+            box.UpdateCounter();
+        }
+    }
 }

Assets/Scripts/AbilityUpgrade.cs

@@ -4,9 +4,22 @@ public class AbilityUpgrade : ScriptableObject
 {
     [Header("Identification")]
     public string upgradeName;
+    public Sprite upgradeIcon;
     public PlayerAbility thisPlayerAbility;
+    [Header("Stats")] 
+    public int count = 1;
 
     public virtual void ApplyUpgrade()
+    {
+        UpgradeEffects();
+    }
+
+    protected virtual void UpgradeEffects()
+    {
+        
+    }
+
+    public virtual void ApplyRemoval()
     {
         
     }

Assets/Scripts/FireBullet.cs

@@ -11,7 +11,6 @@ public class FireBullet : PlayerAbility
     public enum FireMode {Angled, Offset};
     [Header("Projectile")]
     public FireMode fireMode = FireMode.Offset;
-    public float projectileCount;
     public Vector2 offset;
     public float angle;
     [SerializeField] private Projectile projectile;

Assets/Scripts/MarisaAbilityHandler.cs

@@ -18,7 +18,7 @@ public class MarisaAbilityHandler : MonoBehaviour
     public PlayerAbility spellAInstance;
     public PlayerAbility spellBInstance;
 
-    private void Start()
+    private void Awake()
     {
         mainAttackInstance = Instantiate(mainAttack, transform);
         mainAttackInstance.thisPlayer = thisPlayer;

Assets/Scripts/PlayerAbility.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerAbility : MonoBehaviour
@@ -13,6 +14,8 @@ public class PlayerAbility : MonoBehaviour
     private float currentCooldown;
     [Header("Stats")]
     public float power;
+    public float projectileCount;
+    public HashSet<AbilityUpgrade> attachedUpgrades = new();
     
     public void TryAbility()
     {

Assets/Scripts/ProjectileCountUpgrade.cs

@@ -0,0 +1,10 @@
+using UnityEngine;
+
+[CreateAssetMenu(fileName = "Projectile Count Upgrade", menuName = "AbilityUpgrades/ProjectileCountUpgrade")]
+public class ProjectileCountUpgrade : AbilityUpgrade
+{
+    protected override void UpgradeEffects()
+    {
+        thisPlayerAbility.projectileCount++; //idk how this will work for the stacking.
+    }
+}

Assets/Scripts/ProjectileCountUpgrade.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: abe88be260cd4b175b742754eaee097f

Assets/Scripts/UpgradeBoxUI.cs

@@ -0,0 +1,14 @@
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public class UpgradeBoxUI : MonoBehaviour
+{
+    [SerializeField] private TextMeshProUGUI counterUI;
+    public Image upgradeImage;
+    public AbilityUpgrade thisAbilityUpgrade;
+    public void UpdateCounter()
+    {
+        counterUI.text = $"x{thisAbilityUpgrade.count}";
+    }
+}

Assets/Scripts/UpgradeBoxUI.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: b89f179fefb96497c879d4a8dd635717