I've put this map into my fast and fun to play maps collection. If you don't want this, let me know. Otherwise, please dimond the collection and try to tweet about it, tell it your friends idk.. to make it popular.

Hey! You have potential, and I like this map! Now you'll get some tips from a master mapmaker :)

1) You know why the textures are brojen? Because you used too high metadata! Since 1.8 blocks with a higher metadata show this strange texture
2) Sometimes the spawnpoint does not work. You can fix it by not making the spawnpoint with /spawnpoint, but doing it like this: There is a marker armorstand, when the player presses the spawnpoint button, the armorstand gets teleported there. a scoreboard DeathCount. Every player with score DeathCount 1 gets teleported to the armorsstand.
3) Don't use dispensers and spawn eggs to spawn monsters. Use /summon! I know, you want a randomizer, but also that can be done with a dispenser dispensing command blocks, a few of them summon silverfish and one gives the player the key
4) You use items with a CanPlaceOn tag. Thats good, but when the player accidently places the item wrong, theres no chance of getting another one, so don't make the entire floor out of that material, only the blocks where the item has to be placed
5) What was the fifhing rood used for?
6) In the beginning the /gamemode 2 @a don't works. Idk why. Why isn't the player in the first romm from the beginning on?

So great work, maybe check out my maps for inspiration and fun!