Updated asteriods, mines, and explosions.

AlientAttack.MonoGame/Things/Asteroids/AsteroidVariantD.cs

@@ -0,0 +1,20 @@
+using AlienAttack.MonoGame.Textures;
+
+namespace AlienAttack.MonoGame.Things.Asteroids;
+
+public class AsteroidVariantD : Asteroid
+{
+    public const int Width = 44;
+    public const int Height = 35;
+
+    protected override string TextureName => TextureNames.Asteriods.VariantD;
+    protected override int MaxHealth => 10;
+
+    public AsteroidVariantD(int x, int y) : base(x, y)
+    {
+        Origin = new(Width / 2, Height / 2);
+        BoundBox = new(0, 0, Width, Height);
+        YVelocity = .5f;
+        XVelocity = 0;
+    }
+}