weird shader problem (correct in editor, weird ingame)

I wrote a simple shader that's basically just bumped-diffuse, but fades out when close to the camera.

It works in the scene (also when playing), but in the game it looks as if the areas that should be transparent is instead the previous frame beeing added additively (relative to the supposed transparency).

I have no idea what's wrong, any ideas ?

here's the shader: Shader "Custom/Planet" { Properties { _Color ("Main Color", Color) = (1,1,1,1) _MainTex ("Base (RGB)", 2D) = "white" {} _BumpMap ("Normalmap", 2D) = "bump" {} _Dist ("FadeOut Distance", float) = 20 //_PlanetFogColor ("fog Color", Color) = (1,1,1,1) }

 SubShader 
 {
     ZWrite On
     Fog { Mode off }
     Tags { "RenderType"="Transparent" "Queue" = "Geometry+1" } //Queue is nodig (anders fout)
     Blend SrcAlpha OneMinusSrcAlpha 
     //Tags { "RenderType" = "Opaque" }
     //LOD 300
 
     CGPROGRAM
     #pragma surface surf Lambert vertex:vert
     
     fixed4 _Color;
     sampler2D _MainTex;
     sampler2D _BumpMap;    
     float _Dist;
     
     fixed4 _PlanetFogColor; //global
     
     float _UsePlanetFog; //global (0 of 1, bool bestaat niet)
     
     struct Input 
     {
         float2 uv_MainTex;
         float2 uv_BumpMap;
         float z;
     };

     void vert(inout appdata_full v, out Input o)
     {
         o.z = (mul(UNITY_MATRIX_MVP, v.vertex)).w;
     }
     
     void surf (Input IN, inout SurfaceOutput o) 
     {
         fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;

         o.Albedo = c.rgb;
         o.Alpha = 1;//c.a;
         o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
         
         if (_UsePlanetFog>0.5)
         {
             float fade = 1;
             if (IN.z<_Dist)
                 fade = IN.z/_Dist;
             fade=sqrt(fade);
             fade = fade*1.05-0.05;
             if (fade<0)    fade=0;

             o.Alpha = fade;
         
             ////o.Albedo = c.rgb;
             //o.Albedo = (c*fade).rgb;//(c*fade + _PlanetFogColor*(1-fade)).rgb;
             ////o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));//normalize(UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap))*fade + float3(0,0,1)*(1-fade)); //normal ook uitfaden //niet meer nodig
             //o.Emission = ((1-fade)*_PlanetFogColor).rgb;//(1-fade)*o.Albedo; //niet ideaal, zou eigenlijk moeten faden naar unlit color, dit is maar een benadering
         }
         //else
         //{
         //    o.Albedo = c.rgb;
         //}
         
         //o.Alpha = 0;
     }
         
     ENDCG  
 }
 
 FallBack "Bumped Diffuse"

}

also, the should fix/change the formatting for code blocks on UnityAnswers, as they never seem to work (Edit: the button dousn't work, but writing it yourself apparently does)