This paper presents the Submit! project which aims to enhance teaching and learning in computing by developing automated web-based tools that assist in providing critical feedback to students about the computer programs they write. By developing sophisticated computer-based tools that will improve our monitoring of student progress and maintenance of consistent standards we aim to provide structured assessment with a level of detail and consistency that would be difficult or impossible to provide manually. By allowing students to use the critiquing tools before final submission of an assignment we offer formative assessment that supports self-directed learning. Submit! has been integrated into many computing units at Macquarie University. Usability evaluations show that Submit! generally effective while needing improvement in certain areas. A preliminary study of the impact of Submit! on student results shows that students who make use of the system to get feedback on assignment submissions do better than those who don’t.