I don't really like rating decks but I will give some fixes:

-2 Horus LV4
-2 Level Up!
+1 Spear Dragon
+1 Luster Dragon
+1 Masked Dragon
+1 Torrential Tribute

I no longer use Horus LV4 or Level Up! in my Horus deck. They just aren't worth it and there are a lot of more useful cards. My deck is different than yours, though. If you really feel that those two cards give you an advantage, you should continue to use them. Other guys have already listed the reasons for adding another Luster Dragon and Spear Dragon. I suggest the third Masked Dragon because it gives you more protection, thinning, and searching. Luster Dragon, Masked Dragon, and Torrential Tribute are available as commons so they are not hard to trade for. Spear Dragon is a super but it's still pretty easy to get. I think you should playtest without LV4 and Level Up! for a little while, and if it works, drop them. If it doesn't, put them back.

I have tried it without...but I like having them in. It sometimes allows me to get Lv.8 on my second turn!