i would be wary of setting such a short timeframe. sound and art and ui and turorials and all the little bugs here and there tend to result in major extensions. take your expected time and multiply by three is the industry rule of thumb iirc
well the game's almost 80% programmed all that would be left are just assets art and sound. i already have a ton of unused models i cant wait to make use of and as far as art goes i'd only really use it on the UI, which im designing to be simplistic as forget
ive been doing unit and integration testing up the ass so i know everything has been bug tested thoroughly already. the only source of bugs i can imagine would be the not-yet-made save system
the 4 month deadline is just for the game to pass the system tests, there'd probably be another month dedicated for acceptance testing, as well as a month or two after for beta tests. all of these deadlines are subject to change but im definitely going to try and keep all development under 8 months