Systems and methods for hydroprocessing a heavy oil feedstock, the system employs a plurality of contacting zones and separation zones with at least some of the heavy oil feedstock being supplied to at least a contacting zone other than the first contacting zone. The contacting zones operate under hydrocracking conditions, employing a slurry catalyst for upgrading the heavy oil feedstock, forming upgraded products of lower boiling boiling hydrocarbons. In the separation zones, upgraded products are removed overhead and optionally, further treated in an in-line hydrotreater. At least a portion of the non-volatile fractions recovered from at least one of the separation zones is recycled back to the first contacting zone in the system.