Yup, both ъ and ь either modify the preceding constant (тварь) or insert a sort of separation between letters (подъезд).

There are also some non-phonetic aspects to the language, which I didn't really think about until taking Russian in college (sort of native speaker, took the class to make some friends.) For instance, "o" is frequently pronounced as "ah" (хорошо - horosho - is usually pronounced as 'harasho'.)

Every language has quirks.