1. It's very slow compared to Darkness Fire Buster and the WFD/WFN/DFN + Rafululu Busters i often use. When i can run a one shot on the opponent it's pretty much turn 7 or 8 unless my opponent attacks me and triggers a The=Deadbrachio Strike Back. Sure it kills off all defenses if done correctly but i've saw it and even hamubusters can rush me dead.
2. Color Screws: It's pretty much impossible to run Johnny Walker/Dark Life on turn 2 without sacrificing important defense structures like The=Deadbrachios And by the time it runs out it should be around turn 3 or 5. Linnevenus also needs multicolored mana arms 4 too so you might get color screwed sometimes.
3. Graving Problems: Graving is very hard for 5c buster from my experience since you can only mill your deck but never discarding your hand save for Doguraeater which you maybe will run only 1 in your deck. Sometimes the cards are in the seals which are better because you do run some Fire Commands so Dokindam X can give you some of the parts, and Strike Back can have you grave from shields, but otherwise if the cards end up in your hand it's very difficult to have key parts end up in your grave. The reason i say this is because Linnevenus requires the Grave to bring out Shortshot and Rafululu. You can let your opponent kill your shortshots but for Rafululu it does not work.
4. TCO Shuffles, i've saw decks with only 1 Shortshot and 1 Entertainer in some IRL 5c Busters but i prefer Shortshot only in all my 5c busters and you need 3 Shortshots and 2-3 Rafululus to make the thing work consistently.
5. Evil Heat's restriction makes it much slower, but it functions ok anyways with only 1 copy.
Anyway, it's a very troublesome deck and it doesn't look like it's for tco play.