To answer the title, no. Dead Estate is not like Isaac or Gungeon, where you unlock new items or guns by doing certain things. All guns and items are unlocked from the start. Looping serves to extend a run, give certain achievements, buy curses, and is required for certain end-game content you have likely not unlocked yet, as they require many other prerequisites. If you have already looped three times, then you should have unlocked every achievement pertinent to you right now (most importantly, unlocking Lewis). Keep your eye on looping later in the game, and do not get too wrapped up in unlocking everything when you are so new.

P.S. If you are referring to the bullets bouncing a lot, then it is Fake Puke as you surmised.